The weekly demand for drinking-water product, in thousands of liter, from a local chain of efficiency stores is a continuous random variable X having the probability density:
f(x)={2(x−1) 1 0 elsewhere
The values are:
E(X)=53E(X2)=176

Answers

Answer 1

If X is a continuous random variable having the probability density:

f(x)={2(x−1) 1 0 elsewhere then the variance of X is 1/6.

To find the variance of X, we need to use the formula:

Var(X) = [tex]E(X^2)[/tex] - [tex][E(X)]^2[/tex]

To find the expectation E(X) and E(X^2) for the continuous random variable X with the given probability density function (pdf), we integrate the respective expressions over the entire support of the random variable.

Given the pdf:

f(x) = { 2(x - 1), 1, 0 elsewhere }

We can calculate E(X) as follows:

E(X) = ∫x*f(x) dx

      = ∫x*2(x - 1) dx

      = 2∫([tex]x^2[/tex] - x) dx

      = 2[([tex]x^3[/tex]/3) - ([tex]x^2[/tex]/2)] evaluated from 0 to 1

      = 2[(1/3) - (1/2) - (0 - 0)]

      = 2[(1/3) - (1/2)]

      = 2[-1/6]

      = -1/3

Similarly, we can calculate E(X^2) as follows:

E(X^2) = ∫[tex]x^2[/tex]*f(x) dx

         = ∫[tex]x^2[/tex]*2(x - 1) dx

         = 2∫([tex]x^3[/tex] - [tex]x^2[/tex]) dx

         = 2[([tex]x^4[/tex]/4) - ([tex]x^3[/tex]/3)] evaluated from 0 to 1

         = 2[(1/4) - (1/3) - (0 - 0)]

         = 2[(1/4) - (1/3)]

         = 2[1/12]

         = 1/6

Therefore, the expectation E(X) is -1/3 and E(X^2) is 1/6 for the given continuous random variable X with the specified pdf.

Therefore, the variance of X is 1/6.

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Related Questions

evaluate the integral by making an appropriate change of variables. double integral (x y)8e^x^2 y^2da, where r is the rectangle enclosed by the lines x-y=0, x-y=2, x y=0, and x y=3

Answers

The value of the integral is approximately 106.438.

To evaluate the integral, we can make the substitution u = x² and v = y². Then, we have the Jacobian of the transformation as J = 2xy.

Next, we need to find the new limits of integration for u and v.

When x-y=0, we have u - v = 0, so u = v. When x-y=2, we have u - v = 2, so u = v + 2. When xy=0, either u or v must be 0. When xy=3, we have u × v = 3.

Converting these limits of integration to u and v, we have:

0 <= v <= 3/u
v <= u <= v+2

Using the Jacobian and the change of variables, the original integral becomes:

double integral (x y)8e^x² y²da = double integral (uv)8e^(u+v) × 2√(uv) dudv

Integrating with respect to u first, we get:

integral from v to v+2 of [16√(v) × e^(u+v)] du

Using integration by parts, we can evaluate this integral to get:

16sqrt(v) × (e^(2v) - e^v)

Then, integrating with respect to v, we get:

integral from 0 to 3/u of [16sqrt(v) × (e^(2v) - e^v)] dv

This integral can be evaluated using integration by parts again, and we get:

32/3 × (u^(3/2) - 1/e × u^(3/2))

Finally, substituting back in for u and v, we have:

integral from 0 to 3 of [32/3 × (x^3/2 - 1/e × x^3/2)] dx

This can be evaluated using basic calculus, and the final answer is:

(32/3) × (27/2 - 2/e)

Therefore, the value of the integral is approximately 106.438.

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A survey of 1000 adults in the US conducted in March 2011 asked "Do you favor or oppose 'sin taxes' on soda and junk food? The proportion in favor of taxing these foods was 32 %.
(a) Find a 90% confidence interval for the proportion of US adults favoring taxes on soda and junk food.
(b) What is the margin of error?
(c) If we want a margin of error of only 1% (with 90% confidence), what sample size is needed?

Answers

(a) A 90% confidence interval for the proportion of US adults favoring taxes on soda and junk food is (0.293, 0.347).

(b) The margin of error is 2.7%.

(c) To achieve a 1% margin of error with 90% confidence, a sample size of 6,811 is needed.


(a) To find the 90% confidence interval, use the formula CI = p ± Z * √(p(1-p)/n), where p is the proportion, Z is the Z-score for 90% confidence (1.645), and n is the sample size.
p = 0.32, n = 1000
CI = 0.32 ± 1.645 * √(0.32(1-0.32)/1000) = (0.293, 0.347)

(b) The margin of error is half the width of the confidence interval.
Margin of error = (0.347 - 0.293) / 2 = 0.027 or 2.7%.

(c) To find the needed sample size for a 1% margin of error, use the formula n = (Z²* p * (1-p)) / E², where E is the desired margin of error (0.01).
n = (1.645² * 0.32 * (1-0.32)) / 0.01² = 6810.8, rounding up to 6,811.

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a uniform cylinder of radius r, mass m, and length l rotates about a horizontal axis that is parallel and tangent to the cylinder. the moment of inertia of the sphere about this axis is
a. 1/2MR^2
b. 2/3MR^2
c. MR^2
d. 3/2MR^2
e. 3/4MR^2

Answers

The moment of inertia of the cylinder about the given axis is (3/2)mr². Option d is correct.

The moment of inertia of a uniform cylinder of radius r and mass m rotating about its central axis (perpendicular to its length) is (1/2)mr². However, in this case, the cylinder is rotating about a horizontal axis that is parallel and tangent to the cylinder. This axis passes through the center of the cylinder, so we can use the parallel axis theorem to find the moment of inertia about the given axis.

The parallel axis theorem states that the moment of inertia of a rigid body about any axis parallel to its center of mass axis is equal to the moment of inertia about the center of mass axis plus the product of the mass of the body and the square of the distance between the two axes.

In this case, the distance between the center of the cylinder and the given axis is (1/2)l. Therefore, the moment of inertia of the cylinder about the given axis is:

I = (1/2)mr² + m((1/2)l)²= (1/2)mr² + (1/4)ml²= (1/2)mr² + (1/4)m(2r)²= (1/2)mr² + mr²= (3/2)mr²

Therefore, the moment of inertia of the cylinder about the given axis is (3/2)mr², which is option (d).

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30 POINTS!!! Alisha's soccer team is having a bake sale. Alisha decides to bring chocolate chip cookies to sell. There is a proportional relationship between the number of cookies Alisha sells, x, and the total cost (in dollars), y. Alisha sells 6 cookies for $12.00. Which equation shows the relationship between x and y?
A: y = 2x
B: y = 6x
C: y = 12x
D: y = 0.5x
Answer only if you know answer ty

Answers

Answer:

Step-by-step explanation:

2x

The equation which shows the relationship between x and y is A: y = 2x.

What is an Equation?

An equation is the statement of two expressions located on two sides connected with an equal to sign. The two sides of an equation is usually called as left hand side and right hand side.

Given that,

Alisha's soccer team is having a bake sale.

Alisha decides to bring chocolate chip cookies to sell.

There is a proportional relationship between the number of cookies Alisha sells, x, and the total cost (in dollars), y.

Proportional relationships are relationships for which the equations are of the form y = kx, where k is a constant.

Alisha sells 6 cookies for $12.00.

That is, total cost, y = 12 when the number of cookies, x = 6.

The equation becomes,

12 = 6k

k = 12/6 = 2

Required equation is y = 2x.

Hence the required equation is y = 2x.

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Let X be a random variable from a Chi-Square Distribution with 19 degrees of freedom. Megan is interested in the random variable Y=aX+b. She knows that E(Y)=27 and V(Y)= 608.What are all possible values of aa and bb that satisfy this criteria?Write your answer as an ordered pair, (a,b). If there are multiple solutions, separate the ordered pairs by a comma.

Answers

The possible values of a and b that satisfy the criteria are (4, -49) and (-4, 103).

Explain step by step about how to find the possible values of a and b?

We need to use the properties of the Chi-Square Distribution.

Given: X is a random variable from a Chi-Square Distribution with 19 degrees of freedom. We have Y = aX + b, where E(Y) = 27 and V(Y) = 608.

Step 1: Compute E(X) and V(X) for a Chi-Square Distribution with 19 degrees of freedom.
E(X) = ν, where ν is the degrees of freedom.
E(X) = 19

V(X) = 2ν
V(X) = 2(19) = 38

Step 2: Use the properties of expected value and variance to find the expressions for E(Y) and V(Y) in terms of a and b.
E(Y) = E(aX + b) = aE(X) + b
V(Y) = V(aX + b) = a² × V(X)

Step 3: Plug in the given values for E(Y) and V(Y) and solve for a and b.
27 = a(19) + b (1)
608 = a² × 38

Step 4: Solve for a.
a² = 608/38
a² = 16
a = ±4

Step 5: Solve for b using the value of a.
For a = 4:
27 = 4(19) + b
27 = 76 + b
b = -49

For a = -4:
27 = -4(19) + b
27 = -76 + b
b = 103

Step 6: Write the answer as ordered pairs.
The possible values of a and b that satisfy the criteria are (4, -49) and (-4, 103).

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section 6.3: problem 7 make a substitution to express the integrand as a rational function and then evaluate the integral.2∫〖cos⁡x/(6 sin^2+7 sin⁡x ) dx=〗

Answers

The required answer is 2[(1/7) ln |sin(x)| - (1/6) ln|6sin(x)+7|] + C

To solve the integral 2∫cos(x)/(6sin^2(x) + 7sin(x)) dx, we will first make a substitution to express the integrand as a rational function.

A rational function is a polynomial divided by a polynomial. f(x) = x/x-3 is a rational function .Rational functions are used to approximate or model more complex equations . integrals (antiderivative functions) of rational functions. Any rational function can be integrated by partial fraction decomposition of the function into a sum of functions.  In this case, one speaks of a rational function and a rational fraction over K.

The integrand as a rational function and then evaluate the integral.


Step 1: Make a substitution
Let u = sin(x), so du = cos(x) dx.

The integral now becomes:

2∫(du) / (6u^2 + 7u)

Step 2: Express the integrand as a rational function
Since the integrand is already a rational function, no further simplification is needed.

Step 3: Evaluate the integral

2∫(1/7) du - ∫(1/(6u+7)) du] = 2[(1/7) ln |u| - (1/6) ln|6u+7|] + C


To evaluate the integral, we perform partial fraction decomposition on the integrand:
A rational function is any function that can be defined by a rational fraction, which is an algebraic fraction such that both the numerator and the denominator are polynomials. The coefficients of the polynomials need not be rational numbers; they may be taken in any field K. In this case, one speaks of a rational function and a rational fraction over K.

A constant function such as f(x) = π is a rational function since constants are polynomials. The function itself is rational, even though the value of f(x) is irrational for all x. Rational functions are used to approximate or model more complex equations


2∫(du) / (6u^2 + 7u) = 2∫(A/u + B/(6u+7)) du

By clearing the denominators, we get:

1 = A(6u+7) + B(u)

Now, we can solve for A and B:

When u = 0, 1 = 7A => A = 1/7
When u = -7/6, 1 = B(-1) => B = -1

So the integral becomes:

2∫((1/7)/u - 1/(6u+7)) du

Now, we can integrate each term:

2 [∫(1/7) du - ∫(1/(6u+7)) du] = 2[(1/7) ln |u| - (1/6) ln|6u+7|] + C

Step 4: Substitute back in terms of x

Finally, substitute u = sin(x) back into the equation:

2[(1/7) ln |sin(x)| - (1/6) ln|6sin(x)+7|] + C

This is the evaluated integral.

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For a continuous random variable X, P(28 ≤ X ≤ 75) = 0.15 and P(X > 75) = 0.14. Calculate the following probabilities. (Leave no cells blank - be certain to enter "0" wherever required. Round your answers to 2 decimal places.)
a. P(X < 75) b. P(X < 28) c. P(X = 75)

Answers

The required probabilities are

a. P(X < 75) = 0.29, b. P(X < 28) = 0, and c. P(X = 75) = 0

Continuous Probability Distributions:

A continuous probability distribution is a type of probability distribution that describes the probabilities of all possible values that a continuous random variable can take within a specific range.

In contrast to discrete probability distributions, which describe the probabilities of discrete outcomes, continuous probability distributions describe the probabilities of continuous outcomes.

Here we have

For a continuous random variable X,

P(28 ≤ X ≤ 75) = 0.15 and P(X > 75) = 0.14

Given probabilities can be calculated as follows

a. P(X < 75)

P(X < 75) = P(X ≤ 75) - P(X = 75)

= 0.15 + 0.14

= 0.29

b. P(X < 28)

P(X < 28) = P(X ≤ 28) = 0,

[ since X cannot be less than 28 if P(28 ≤ X ≤ 75) = 0.15 ]

c. P(X = 75)

P(X = 75) = P(X ≤ 75) - P(X < 75)

= 0.15 - 0.29

= -0.14.

However, this is not a valid probability since probabilities cannot be negative.

Therefore, P(X = 75) = 0.

Therefore,

The required probabilities are

a. P(X < 75) = 0.29, b. P(X < 28) = 0, and c. P(X = 75) = 0

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What value of x does not satisfy the equation sin 2x + sinx = 0? (a) 7/2 (b) 3/2 (c) 271 (d) 3 (e) All Satisfy What value of x does not satisfy the equation sin x + sin x = 0 ? (a) 7/2 (b) 31/2 (c) (d) 2 (e) All Satisfy

Answers

For the first equation, the value of x that does not satisfy the equation sin 2x + sin x = 0 is (c) 271.

For the second equation, all values of x satisfy the equation sin x + sin x = 0, and the answer is (e) All Satisfy.

How to find the value of x?

For the first equation of Trigonometry, sin 2x + sin x = 0, we can use the identity sin 2x = 2 sin x cos x to rewrite it as:

2 sin x cos x + sin x = 0

Factoring out sin x, we get:

sin x (2 cos x + 1) = 0

So the equation is satisfied when sin x = 0 or 2 cos x + 1 = 0. Solving the second equation for cos x, we get:

2 cos x = -1

cos x = -1/2

So the equation is satisfied when sin x = 0 or cos x = -1/2.

The values of x that satisfy these conditions are x = nπ (where n is an integer) and x = (2n+1)π/3 (where n is an integer).

Therefore, the value of x that does not satisfy the equation sin 2x + sin x = 0 is (c) 271.

For the second equation, sin x + sin x = 0, we can simplify it to:

2 sin x = 0

This equation is satisfied when sin x = 0, which occurs at x = nπ (where n is an integer).

Therefore, all values of x satisfy the equation sin x + sin x = 0, and the answer is (e) All Satisfy.

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A coin is tossed 19 times. In how many outcomes do exactly 5 tails occur? a) 95 b) 120 c) 11,628 d) O1,395 360 f) None of the above

Answers

The answer is b) 120.

To solve this problem, we can use the binomial probability formula:

P(X=k) = (n choose k) * p^k * (1-p)^(n-k)
Where:
- n is the number of trials (in this case, 19)
- k is the number of successes we want (in this case, 5)
- p is the probability of getting a tail on a single coin toss (which is 0.5 for a fair coin)
- "n choose k" is a combination formula that gives us the number of ways to choose k items from a set of n items (it can be calculated as n!/(k!(n-k)!))

Plugging in the values, we get:
P(X=5) = (19 choose 5) * 0.5^5 * 0.5^(19-5)
P(X=5) = (19 choose 5) * 0.5^19
P(X=5) ≈ 0.2026

Finally, we need to multiply this probability by the total number of possible outcomes (which is 2^19, since there are 2 possible outcomes for each toss):

Total number of outcomes with 19 coin tosses = 2^19 = 524,288
Number of outcomes with exactly 5 tails = 0.2026 * 524,288 ≈ 106,288
Therefore, the answer is b) 120.

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An electrician has 42.3 meters of wire to use on a job on the first day she uses 14.742 meters of the wire how much meters of wire does she have remaining after the first day

Answers

The amount of wire does she have remaining after the first day is,

⇒ 27.558 meters

We have to given that;

An electrician has 42.3 meters of wire to use on a job on the first day she uses 14.742 meters of the wire.

Now, We can formulate;

The amount of wire does she have remaining after the first day is,

⇒ 42.3 - 14.742

⇒ 27.558 meters

Thus, The amount of wire does she have remaining after the first day is,

⇒ 27.558 meters

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A 9-pound bag of sugar is being split into containers that hold 3/4
of a pound. How many containers of sugar will the 9-pound bag fill

Answers

The 9-pound bag of sugar will fill 12 containers that hold 3/4 of a pound.

evaluate dy for the given values of x and dx. y = cosπx, x = 1 3 , dx = −0.02.

Answers

The derivative of the function y = cosπx at x = 1 is 0.02sinπ(1) - 0.02sinπ(0.98).

What is function?

Function is a block of code that performs a specific task. It is a self-contained unit of code that takes inputs, performs certain operations, and returns an output. Functions are often used to reduce code repetition and increase code readability. It is also used to make programs more efficient and easier to maintain.

Using the definition of the derivative, we can calculate dy by taking the limit as dx approaches 0.

dy = lim dx→0 (cosπ(1 + dx) - cosπ(1))/dx

= lim dx→0 (cosπ(1 - 0.02) - cosπ(1))/(-0.02)

= lim dx→0 (cosπ(0.98) - cosπ(1))/(-0.02)

= lim dx→0 (-(cosπ(1) - cosπ(0.98))/-0.02)

= lim dx→0 (0.04sinπ(1) - 0.04sinπ(0.98))/0.02

= lim dx→0 (0.04sinπ(1) - 0.04sinπ(0.98))/0.02

= (0.04sinπ(1) - 0.04sinπ(0.98))/0.02

= 0.02sinπ(1) - 0.02sinπ(0.98)

Therefore, dy = 0.02sinπ(1) - 0.02sinπ(0.98).

This calculation shows that the derivative of the function y = cosπx at x = 1 is equal to 0.02sinπ(1) - 0.02sinπ(0.98). This result is consistent with the definition of the derivative, which states that the derivative is the rate of change of a function with respect to its independent variable. In this case, the rate of change of the cosine function with respect to x is 0.02sinπ(1) - 0.02sinπ(0.98).

In conclusion, the derivative of the function y = cosπx at x = 1 is 0.02sinπ(1) - 0.02sinπ(0.98).

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this is section 3.1 problem 14: for y=f(x)=− 2 x , x=2, and δx=0.2 : δy= , and f'(x)δx . round to three decimal places unless the exact answer has less decimal places.

Answers

The derivative of f(x) is f'(x) = -2, so we can substitute these values into the formula to get δy = -2 * 0.2 = -0.4.

How to calculate the change in the output variable y?

This problem involves using the concept of the derivative to calculate the change in the output variable y, given a small change in the input variable x.

Specifically, we are given the function y = f(x) = -2x, the value of x at which we want to evaluate the change, x = 2, and the size of the change in x, δx = 0.2.

To find the corresponding change in y, δy, we can use the formula δy = f'(x) * δx, where f'(x) is the derivative of f(x) evaluated at x.

In this case, the derivative of f(x) is f'(x) = -2, so we can substitute these values into the formula to get δy = -2 * 0.2 = -0.4.

This tells us that a small increase of 0.2 in x will result in a decrease of 0.4 in y, since the derivative of the function is negative.

This problem illustrates the concept of local linearization, which is the approximation of a nonlinear function by a linear function in a small region around a point.

The derivative of the function at a point gives us the slope of the tangent line to the function at that point, and this slope can be used to approximate the function in a small region around the point.

This approximation can be useful for estimating changes in the output variable given small changes in the input variable.

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a social worker is studying mental health statistics to better understand the clients they may work with. it is known that 5 percent of u.s. adults suffer from a mental illness. after studying this topic and looking at current trends, the social worker believes the percent of u.s. adults who suffer from a mental illness has decreased. what are the hypotheses? fill in the blanks with the correct symbol (

Answers

The null hypothesis would be H0: p = 0.05. The alternative hypothesis would be Ha: p < 0.05.

When forming hypotheses in this context, we typically state a null hypothesis (H0) and an alternative hypothesis (H1). Here's how you can fill in the blanks:

Null hypothesis (H0): The percentage of U.S. adults who suffer from a mental illness has not changed. H0: p = 0.05

Alternative hypothesis (H1): The percentage of U.S. adults who suffer from a mental illness has decreased. H1: p < 0.05

In this case, "p" represents the percentage of U.S. adults with a mental illness. The social worker will use statistical tests to analyze data and determine if there is enough evidence to reject the null hypothesis in favor of the alternative hypothesis.

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determine the domain of the following graph

Answers

The domain is (-2,10)

A machine used to regulate the amount of dye dispensed for mixing shades of paint can be set so that it discharges an average of milliers of dye per can of paint. The amount of dye discharged is known to have a normal distribution with a standard deviation equal to 0.1342. If more than 6,4 milliliters of dye are discharged when making a particular shade of blue paint, the shade is unacceptable. Determine the setting of so that no more than 2.5 of the cans of paint will be unacceptable 8.09 ml 9.08 ml6.13 ml3.23 ml 4.87 ml

Answers

The setting of the machine should be no more than 6.135 milliliters per can of paint to ensure that no more than 2.5% of the cans of paint will be unacceptable.

What is normal distribution?

A continuous probability distribution known as the normal distribution is frequently used to simulate symmetric and bell-shaped real-world phenomena. The mean and the standard deviation are the two factors that define it. Because of its numerous characteristics and uses, the normal distribution is significant in statistics and data analysis. The assumption that the data are normally distributed or may be approximated by a normal distribution is made by many statistical tests and confidence ranges, for instance.

Let us suppose the amount of dye discharged = X.

Thus, X ~ N(μ, σ).

Now, for μ such that no more than 2.5%:

P(X > 6.4) ≤ 0.025

Using the z-score we have:

Z = (X - μ) / σ

P(X > 6.4) = P((X - μ) / σ > (6.4 - μ) / σ) = P(Z > (6.4 - μ) / σ)

(6.4 - μ) / 0.1342 > 1.96

μ < 6.4 - 1.96(0.1342) = 6.135

Hence, the setting of the machine should be no more than 6.135 milliliters per can of paint to ensure that no more than 2.5% of the cans of paint will be unacceptable.

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The circle below is centered on the origin. The hypotenuse of the right triangle within the circle is 5​ units long, has one endpoint at the center of the circle, and the other endpoint is on the circle.

Enter the equation of the circle:

Answers

Answer: x²+y²=25

Step-by-step explanation:

Formula for a circle is:

(x-h)²+(y-k)²=r²

where (h, k) is your center and r is radus.

In your question, (h,k)=(0,0) because it says the center is at the origin and

r=5 because the hypotenuse of that triangle is the radius of the circle

You can substitute into the formula for a cirlcle with (0,0) and r=5

x²+y²=5²

x²+y²=25

Compute E[X] if X has a density function given by f(x) = {1/4 xe^x/2 x > 0 0 otherwise

Answers

If X has a density function given by a function called as f(x), then density function E[X] = ∞.

Since the integral diverges and density function as x approaches infinity, the expected value of X does not exist. This can also be seen by noting that f(x) is a right-skewed distribution with a long tail, and so it does not have a finite mean.

Here E[X], we can use the formula:

E[X] = ∫ x f(x) dx,

Here f(x) is the probability density function of X.

For this problem, we have:

0 otherwise.

So, we can write:

E[X] = [tex]x (1/4 x e^{(x/2)}) dx\\= (1/4) x^2 e^{(x/2)} dx[/tex]

We can use integration by parts with u = [tex]x^2[/tex]and dv/dx = (x/2):

[tex]E[X] = (1/4) [x^2 e^{(x/2)} - 2x e^{(x/2)} dx]\\= (1/4) [x^2 e^{(x/2)} - 4x e^{(x/2)} + 8 e^{(x/2)}] + C[/tex]

HereC is the constant of integration. Since f(x) is a probability density function, it must integrate to 1 over its support (which in this case is (0, ∞)):

∫ f(x) dx = ∫ 1/4 x [tex]e^{(x/2)[/tex] dx = 1

So we can solve for C:

C = -1/2

Therefore, the expected value of X is:

E[X] = [tex](1/4) [x^2 e^{(x/2)} - 4x e^{(x/2)} + 8 e^{(x/2)]} - 1/2[/tex]

To evaluate this expression, we can use the limits of integration (0, ∞):

E[X] = [tex](1/4) [(\alpha )^2 e^(\alpha /2) - 4(\alpha ) e^(\alpha /2) + 8 e^(\alpha /2)] - 1/2[/tex]

= ∞

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Correct Question:

Compute E[X] if X has a density function given by f(x) = {1/4 xe^x/2 if x > 0

or 0 if x < 0

the sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is a. 10. b. 11. c. 117. d. 116.

Answers

The sample size needed to provide a margin of error of 2 or less with a 0.95 probability when the population standard deviation equals 11 is option C, 117.

The formula for the margin of error (E) is:

E = z * (σ / sqrt(n))

where z is the z-score for the desired level of confidence (0.95 corresponds to z = 1.96), σ is the population standard deviation, and n is the sample size.

We are given that σ = 11 and we want the margin of error to be 2 or less with a 0.95 probability, so we can write:

2 = 1.96 * (11 / sqrt(n))

Solving for n, we get:

n = (1.96 * 11 / 2)^2

n ≈ 116.36

Rounding up to the nearest integer, we get n = 117.

Therefore, the sample size needed to provide a margin of error of 2 or less with a 0.95 probability when the population standard deviation equals 11 is option C, 117.

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Universal Pet House sells vinyl doghouses and treated lumber doghouses. It takes the company 5 hours to build a vinyl doghouse and 2 hours to build a treated lumber doghouse. The company dedicates 50 hours every week towards building doghouses. It takes an additional hour to paint each vinyl doghouses and an additional 2 hours to assemble each treated lumber doghouses. The company dedicates 30 hours every week towards assembling and painting doghouses.

Write a system of equations that represent the production time needed to build each doghouse and the production time needed for painting and assembling each doghouse. Use x to represent the number if vinyl doghouses and y to represent the number of treated lumber doghouses

Answers

The  system of equations that represent the production time needed to build each doghouse and the production time needed for painting and assembling each doghouse.

5x + 2y = 50 (The production time for building)

1x + 2y = 30 (The production time for painting and assembling)

What is the equation about?

We shall make x be the number of vinyl doghouses made and y be the number of treated lumber doghouses made.

The time to build x vinyl doghouses = 5x hours,

The time to build y treated lumber doghouses = 2y hours.

Hence: the full time spent building doghouses is:  

5x + 2y hours

The time to paint x vinyl doghouses = 1x hour

The time to assemble y treated lumber doghouses = 2y hours.

Hence total time spent painting and assembling doghouses is:

1x + 2y hours

There is:

50 hours every week towards building doghouses

30 hours every week towards painting and assembling doghouses.

Hence the system of equations that stand for the production time needed to build all of the doghouse as well as painting and assembling each doghouse is:

5x + 2y = 50 (production time for building)

1x + 2y = 30 (production time for painting and assembling)

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Determine the equation of the ellipse with center (10,-8), a focus at (10, -14),
and a vertex at (10, -18).

Answers

Answer:

  (x -10)²/64 +(y +8)²/100 = 1

Step-by-step explanation:

You want the equation of the ellipse with center (10,-8), a focus at (10, -14), and a vertex at (10, -18).

Axes

The length of the semi-major axis is the distance between the center and the give vertex: a = -8 -(-18) = 10 units.

The distance from the center to the focus is -8 -(-14) = 6.

The distance from the center to the covertex is the other leg of the right triangle with these distances as the hypotenuse and one leg.

  b = √(10² -6²) = √64 = 8 . . . . units

Equation

The equation for the ellipse with semi-axes 'a' and 'b' with center (h, k) is ...

  (x -h)²/b² +(y -k)²/a² = 1

  (x -10)²/64 +(y +8)²/100 = 1

__

Additional comment

The center, focus, and given vertex are all on the vertical line x=10, This means the major axis is in the vertical direction, and the denominator of the y-term will be the larger of the two denominators.

You will notice the center-focus-covertex triangle is a 3-4-5 right triangle with a scale factor of 2.

PLEASE HELP ITS URGENT IM SUPER STUCK

Answers

A negative z-score implies that the value is less than the mean. This suggests that the data point is more diminutive than the common amount of data set.

While a z-score of zero reveals that the data point sits at exactly the mean of the data set. Which means, the data point is normal, neither bigger nor smaller than the mean.

How to calculate the value

Substituting the given values and solving for x, we get:

1.80 = (x - 75) / 10

x - 75 = 18

x = 93

Therefore, Brittany's score was 93.

Substituting the given values and solving for μ, we get:

1.25 = (80 - μ) / 4

80 - μ = 5

μ = 75

Therefore, the mean was 75.

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A dietician obtains a sample of the amounts of sugar (in centigrams) in each of 10 different cereals, including Cheerios, Corn Flakes, Fruit Loops and others. 24 30 47 43 7 47 13 44 39 10 Find the mean amount of sugar. - If necessary ROUND to the nearest hundredth place.

Answers

The required answer is the number of cereals (10): 304 / 10 = 30.4

To find the mean amount of sugar in the sample of 10 different cereals, we need to add up all the amounts of sugar and divide by the number of cereals in the sample.
the mean (often simply described as the "average") is that it is not skewed by a small proportion of extremely large or small values, and therefore provides a better representation of the center. Median income,


Adding up the amounts of sugar:

24 + 30 + 47 + 43 + 7 + 47 + 13 + 44 + 39 + 10 = 304

Dividing by the number of cereals (which is 10):

304 / 10 = 30.4
So the mean amount of sugar in the sample is 30.4 centigrams.
If we need to round to the nearest hundredth place, the answer would be 30.40 centigrams.

To find the mean amount of sugar in the 10 different cereals, including Cheerios, Corn Flakes, Fruit Loops, and others, follow these steps:

1. Add up the amounts of sugar in each cereal: 24 + 30 + 47 + 43 + 7 + 47 + 13 + 44 + 39 + 10 = 304 centigrams
2. Divide the total amount of sugar (304 centigrams) by,

the number of cereals (10): 304 / 10 = 30.4

The arithmetic mean (or simply mean) of a list of numbers, is the sum of all of the numbers divided by the number of numbers. Similarly, the mean of a sample. , usually denoted by. , is the sum of the sampled values divided by the number of items in the sample.

the mean (often simply described as the "average") is that it is not skewed by a small proportion of extremely large or small values, and therefore provides a better representation of the center.


The mean amount of sugar in the cereals is 30.4 centigrams. Since it's already rounded to the nearest hundredth place, there's no need for further rounding.

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Rate data often follow a lognormal distribution Average power usage (dB per hour) for a particular company is studied and is known to have a lognormal distribution with parameters 4 and ơ-2. what is the mean power usage (average db per hour)? what is the variance?

Answers

Therefore, the variance of the lognormal distribution for this company is approximately 322196.29 (dB/hour)^2.

To find the mean power usage (average dB per hour) for a lognormal distribution with parameters 4 and ơ-2, we use the formula:

[tex]Mean = e^{u+ o^{2/2}}\\=e^{u+o}[/tex]



where μ is the mean of the logarithm of the data (in this case, μ = 4) and σ is the standard deviation of the logarithm of the data (in this case, σ = -2).

Substituting the values, we get:

Mean = [tex]e^{(4 + (-2)^{2/2}}  

 = e^{(4 + 2)}

   = e^6[/tex]
    ≈ 403.43 dB/hour

Therefore, the mean power usage for this company is approximately 403.43 dB per hour.

To find the variance of the lognormal distribution, we use the formula:
[tex]Variance = (e^{o^2} - 1) * e^{2u + o^2}[/tex]

Substituting the values, we get:

[tex]Variance = (e^(-2) - 1) * e^(2*4 + (-2)^2)\\         = (1/e^2 - 1) * e^(8 + 4)\\         = (1/7.389 - 1) * e^{1/2}\\         = 322196.29[/tex]
Therefore, the variance of the lognormal distribution for this company is approximately 322196.29 (dB/hour)^2.

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Ty
Can somebody help me with this


What are the first two steps of drawing a triangle that has all side lengths equal to 6 centimeters?

Select from the drop-down menus to correctly complete the statements.

Draw a segment (6,9,12) centimeters long. Then from one endpoint, draw a (30,60,90) ° angle.

Answers

The answer of the given question based on the triangle is (a) the coordinate is given wrong so it does not for any equilateral triangle, (b) the steps are given below to draw equilateral triangle.

What is Line segment?

A line segment is  part of  line that is bounded by two distinct endpoints. It can be measured by its length, which is the distance between its endpoints. A line segment is a straight line that extends between its endpoints, but it does not continue indefinitely in either direction.

Draw a segment (6,9,12) centimeters long. Then from one endpoint, draw a (30,60,90) ° angle.

Neither of these steps is correct for drawing an equilateral triangle with all sides equal to 6 centimeters.

To draw an equilateral triangle, we can follow these steps:

Draw a straight line segment of 6 centimeters.

At one endpoint of the segment, use a compass to draw a circle with a radius of 6 centimeters. This will be the circle that intersects the other endpoint of the segment.

Without changing the compass width, place the compass on the other endpoint of the segment and draw a second circle of radius 6 centimeters.

Draw a straight line segment connecting the two points where the circles intersect.

This will create an equilateral triangle with all sides equal to 6 centimeters.

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what is the surface area of the net of the cylinder shown?

Answers

Answer:

=715.92ft-2

Step-by-step explanation:

first find the area of the two circles by 2πr-2

then find the perimeter of one circle and use it as length and multiply it with 13ft and add the areas to get the answer

data from the centers for disease control and prevention indicate that weights of american adults in 2005 had a mean of 167 pounds and a standard deviation of 35 pounds.on october 5, 2005, a tour boat named the ethan allen capsized on lake george in new york with 47 passengers aboard. in the inquiries that followed, it was suggested that the tour operators should have realized that the combined weight of so many passengers was likely to exceed the weight capacity of the boat, 7500 lbs. based on this information, how surprising is it for a sample of 47 passengers to have an average weight of at least 7500/47

Answers

The mean weight of American adults in 2005 was 167 pounds, the tour operators should have been more cautious in evaluating the boat's weight capacity given this information.

To answer this question, we need to use the concept of the sampling distribution of the mean.

We know from the given information that the population mean weight of American adults in 2005 was 167 pounds with a standard deviation of 35 pounds.

However,

We are interested in the average weight of a sample of 47 passengers from the Ethan Allen boat.
Assuming that the weights of the passengers on the boat were normally distributed, we can calculate the standard error of the mean using the formula:
standard error of the mean = standard deviation / square root of sample size
Plugging in the given values, we get:
standard error of the mean = 35 / √47
standard error of the mean ≈ 5.09
Now, to find out how surprising it is for a sample of 47 passengers to have an average weight of at least 7500/47 = 159.57 pounds, we need to calculate the z-score:
z-score = (sample mean - population mean) / standard error of the mean
z-score = (159.57 - 167) / 5.09
z-score ≈ -1.45
Looking at the standard normal distribution table, we can see that the probability of getting a z-score of -1.45 or less is about 0.073.

This means that if we took 100 random samples of 47 passengers from the Ethan Allen boat, we would expect to see a sample mean weight of 159.57 pounds or less in about 7.3 of those samples.
Therefore,

It is not very surprising to see a sample of 47 passengers from the Ethan Allen boat with an average weight of at least 159.57 pounds given the weight capacity of the boat.

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10. The diagram at right shows a circle inscribed in a square. Find the area of the shaded region if the side length of the square is 6 meters.​

Answers

Answer:

3.87cm

hope this helped

Find the linearization of the function z = x squareroot y at the point (6, 1). L(x, y) = Find the linearization of the function f(x, y) = squareroot 36 - 4x^2 - 4y^2 at the point (-1, 2). L(x, y) = Use the linear approximation to estimate the value of f(-1.1, 2.1) =

Answers

Answer:

Step-by-step explanation:

Find the linearization of the function z = x squareroot y at the point (6, 1). L(x, y) = Find the linearization of the function f(x, y) = squareroot 36 - 4x^2 - 4y^2 at the point (-1, 2). L(x, y) = Use the linear approximation to estimate the value of f(-1.1, 2.1) =

Consider the following function. f(x) = ln(1 + 2x), a = 3, n = 3, 2.7 ? x ? 3.3
(a) Approximate f by a Taylor polynomial with degree n at the number a. T3(X) = ?
(b) Use Taylor's Inequality to estimate the accuracy of the approximation
f(x) ? Tn(x) when x lies in the given interval. (Round your answer to six decimal places.) |R3(x)| ? ?
(c) Check your result in part (b) by graphing. |Rn(x)|.

Answers

(a) The taylor polynomial is 3(x) ≈ ln(1 + 6) + (2/7)(x - 3) - (1/21)(x - 3)² + (1/63)(x - 3)³

(b) The accuracy of the approximation is  |R3(x)| ≤ 0.000274

(c) Graphing |R3(x)| confirms the accuracy.

a)  To approximate f(x) = ln(1 + 2x) by a Taylor polynomial with degree n=3 at a=3, find the first three derivatives of f(x) and evaluate them at x=3. Then, use the formula T3(x) = f(3) + f'(3)(x - 3) + f''(3)(x - 3)²/2! + f'''(3)(x - 3)³/3!.

b) Use Taylor's Inequality to estimate the accuracy of the approximation for the given interval, 2.7 ≤ x ≤ 3.3. First, find the fourth derivative of f(x), then find its maximum value in the interval. Finally, use the formula |R3(x)| ≤ (M/4!)(x - 3)^4, where M is the maximum value of the fourth derivative.

c) To check the result from part (b), graph the remainder function |R3(x)| in the given interval. If the maximum value of the graph is close to the value found in part (b), this confirms the accuracy of the approximation.

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Suppose an industry consists of 100 firms with identical cost structures (represented by the "typical individual firm" in the figure below). The price is $18. Instructions: Plot the profit-maximizing quantity using the tool provided (Q). Price/Cost (S) 60 50 MC 40 F AVC 30 20 F 10 F 10 20 30 40 50 60 Quantity Ask Instructions: Round your answers to the nearest whole number. Print The firm output quantity at the equilibrium price is References units The market output quantity at the equilibrium price is units When you enter data into a database, the program actually enters information into one or more related ___. a. Fiscal Policy involves changing Click to select) In the United States, Fiscal Policy is implemented by the (Cick to select) b. (Click to select) (Click to select can be used to address a Recessionary Gap by (Click to select taxes and Click to select government purchases. 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In the context of Diana Baumrinds parenting styles, children of authoritative parents differ from children of authoritarian parents in that children of authoritative parents According to EPA guidelines the permissible level for lead in drinking water is 15 parts per billion (ppb). What is the maximum allowable mass of lead that could be present in 1.00 L of H_2O?A.0.015 ngB.0.015 gC.0.015 mgD.0.015 g The value of the logarithmic function log 2 log 2 log 2 16 is equal to a. 0 b. 1 c. 2 d. 4 In an effort to increase sales, a company is considering a new training program for its sales department. An advertisement claims that the training program leads to a mean increase of $5000 in monthly sales. To study the program's effectiveness, the company selects 20 sales representatives, randomly assigning 10 to the training program and 10 to serve as control. On average, the representatives who participated in the training brought in $8231 more in monthly sales than the control, and the 95% confidence interval for the difference in means was (2799, 13663) dollars. Does this confidence interval provide convincing statistical evidence that the mean increase in sales is different from the advertised value?A) No, because $0 is outside the interval the results are not statistically significant.B) No, because $5000 is included in the interval the results not statistically significant.C) Yes, because $0 is outside the interval the results are statistically significant. D) Yes, because the representatives were randomly assigned and $8231 is different from $5000.E) Yes, because $8231 is inside the confidence interval the results are accurate. Solve the simultaneous equations 2x + 4y =1 3x 5y =7the first thing you want to do is make both of the equations the same. the way you would do this is:2x + 4y =1 53x 5y =7 410x + 20y =512x - 20y =28the reason for doing this is to find what one of th3 equations equal to. meaning that by making one of the sets of letters+numbers the same, we can find out what the other set of letters+numbers to find what x and y equal to.so we have to:10x + 20y =5 -20y12x - 20y =28 +20y22x =33the season for adding the 10x and 12x is because when adding a minus and an addition number we add. you would only need to subtract if it's sss (same sign subtract) which isn't in this case. with 22x =33, we divide both sides by 22 to get x on its own. making x to equal 1.5to find y, we have to sub in x with 1.5so, you would do:2 1.5 +4y =12 1.5 = 33 + 4y =1-3 -34y = -2y = -1/2x = 1.5y = -1/2 SPRING BREAK GEOMETRY HW Determine the LSRL for determining temperature (Response Variable) as it relates to wind speed (Explanatory Variable). 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He created an internal website where employees could voice their concerns about the acquisition and ask questions about future roles and the direction of the organization. He produced a 360-degree performance feedback system that gave both old and new employees an opportunity to evaluate their colleagues. Finally, he added a team-based incentive to the compensation program to reward employees based on meeting group goals. Six months after initiating these practices, he wants to evaluate and report on their effectiveness.1. What type of data should be collected for this evaluation?A. the costs associated with each of the programsB. salary info from competitorsC. employee demographicsD. employee assessmentsE. surveys of top executives2. What should be the focus of the evaluation?A. employee surveysB. reviewing key indicators of successC. evaluating staffing proceduresD. the cost of the new programsE. whether the revised practices can be implemented3. 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