A magazine includes a report on the energy costs per year for​32-inch liquid crystal display​ (LCD) televisions. The article states that 14 randomly selected​ 32-inch LCD televisions have a sample standard deviation of ​$3.42 . Assume the sample is taken from a normally distributed population. Construct 98 ​% confidence intervals for​ (a) the population variance sigma squared and​ (b) the population standard deviation sigma .
Interpret the results. ​(a) The confidence interval for the population variance is ​(___,___ ​). ​(Round to two decimal places as​ needed.)
Interpret the results. Select the correct choice below and fill in the answer​ box(es) to complete your choice. ​(Round to two decimal places as​ needed.)
A. With 98 ​% ​confidence, you can say that the population variance is less than ___.
B. With 2 ​% ​confidence, you can say that the population variance is between nothing and ___ .
C. With 98 ​% ​confidence, you can say that the population variance is between ___ and ___ .
D. With 2 ​% ​confidence, you can say that the population variance is greater than ___
​(b) The confidence interval for the population standard deviation is ​(n___,___​). ​(Round to two decimal places as​needed.)
Interpret the results. Select the correct choice below and fill in the answer​ box(es) to complete your choice. ​(Round to two decimal places as​ needed.)
A. With 98​% ​confidence, you can say that the population standard deviation is between ___ and ___ dollars per year.
B. With 98​% ​confidence, you can say that the population standard deviation is greater than ___ dollars per year.
C. With 2​% ​confidence, you can say that the population standard deviation is less than ___ dollars per year.
D. With 2​% ​confidence, you can say that the population standard deviation is between ___ and ___ dollars per year.

Answers

Answer 1

Answer:

a

The confidence interval for the population variance is ​[tex] 5.49 < \sigma^2 < 37.02 [/tex]  

The correct option is  C

b

The confidence interval for the population standard deviation is [tex] 2.34 < \sigma < 6.08 [/tex]

The correct option is  A

Step-by-step explanation:

From the question we are told that

    The sample size is  n =  14

    The standard deviation is  [tex]s = \$3.42[/tex]

Generally the degree of freedom is mathematically represented as

     [tex]df =  14 -1[/tex]

=>   [tex]df =  13 [/tex]    

Given that the confidence level is  98%  then that level of significance is  

     [tex]\alpha = (100 -98) \%[/tex]

=>  [tex]\alpha = 0.02[/tex]

Generally the 98% confidence interval for the variance  is mathematically represented as

     [tex]\frac{(n- 1) s^2}{x^2 _{[\frac{\alpha }{2} , df]}}  < \sigma^2 < \frac{(n- 1) s^2}{x^2 _{[1- \frac{\alpha }{2} , df]}}[/tex]

=> [tex]\frac{(14- 1) (3.42)^2}{x^2 _{[\frac{0.02 }{2} , 13]}}  < \sigma^2 < \frac{(14- 1) (3.42)^2}{x^2 _{[1- \frac{0.02 }{2} , 13]}}[/tex]

From the chi -distribution table  

     [tex]x^2 _{[1- \frac{0.02 }{2} , 13]} = 4.107[/tex]

and

    [tex]x^2 _{[\frac{0.02 }{2} , 13]} = 27.689[/tex]

So

=> [tex]\frac{(14- 1) (3.42)^2}{27.689}  < \sigma^2 < \frac{(14- 1) (3.42)^2}{4.107}[/tex]    

=> [tex] 5.49 < \sigma^2 < 37.02 [/tex]    

Generally the 98% confidence interval for the standard deviation   is mathematically represented as

   [tex]\sqrt{\frac{(n- 1) s^2}{x^2 _{[\frac{\alpha }{2} , df]}}}   < \sigma <\sqrt{ \frac{(n- 1) s^2}{x^2 _{[1- \frac{\alpha }{2} , df]}}}[/tex]

=> [tex]\sqrt{5.49}  < \sigma < \sqrt{37.02 }[/tex]

=> [tex] 2.34 < \sigma < 6.08 [/tex]


Related Questions

. If BC=46.5 and AC=82.3 Find AB.

Answers

82.3-46.5
Answer
35.8

2.1 + 1.4 Find The Sum :)

Answers

3.5 !! good luck girl

What is the midpoint between 10,-3 and -4,-9

Answers

Answer:

(3,3)

Step-by-step explanation:

Use the midpoint formula to find your answer. The formula is [tex](x_{1} +x_{2} /2; y_{1} +y_{2} /2)[/tex].

If that equation looks funny then let me explain. You need to add 10 and -4 together, then divide it by 2. You also need to add -3 and -9, then divide that by 2.

2.) What is the perimeter of a polygon with vertices at (-3, 1), (5, 1), (-3, 4), (5, 4)?

Answers

Answer:

33.1 units

Step-by-step explanation:

The formula to find the sides of an shape when given vertices is

= √(x2 - x1)² + (y2 - y1)²

When we have:(x1, y1) and (x2, y2)

(-3, 1), (5, 1), (-3, 4), (5, 4)

For (-3, 1), (5, 1)

= √(5 - (-3))² + (1 -1)²

= √8² + 0²

= √64

= 8 units

For (5, 1), (-3, 4)

= √(-3 - 5)² + (4 - 1)²

= √-8² + 3²

= √64 + 9

= √73 units

For (-3, 4), (5, 4)

= √(5 - (-3))² + (4 - 4)²

= √8² + 0²

= √64

= 8 units

For (-3, 1), (5, 4)

= √(-3 - 5)² + (4- 1)²

= √8² + 3²

= √64 + 9

= √ 73 units

Perimeter of the Polygon:

=( 8 + √73 + 8 + √73) units

= 33.088007491 units

≈ 33.1 units

The equation P = 6s represents the perimeter P of a regular hexagon with side length s. What is the perimeter of a regular hexagon with side length 7 m?​

Answers

Answer: 42

Step-by-step explanation:

The required perimeter of the regular hexagon is 42 m.

Given that,
The equation P = 6s represents the perimeter P of a regular hexagon with side length s. What is the perimeter of a regular hexagon with side length 7 m is to be determined.

What is the perimeter?

Perimeter is the measure of the figure on its circumference.

here,
the perimeter of the regular hexagon is given,
P = 6s
Put s = 7
P = 6(7)
p = 42

Thus, the required perimeter of the regular hexagon is 42 m.

Learn more about perimeter here:

brainly.com/question/6465134

#SPJ2


Restless Leg Syndrome and Fibromyalgia
People with restless leg syndrome have a strong urge to move their legs to stop uncomfortable sensations. People with fibromyalgia suffer pain and tenderness in joints throughout the body. A recent study indicates that people with fibromyalgia are much more likely to have restless leg syndrome than people without the disease. The study indicates that, for people with fibromyalgia, the probability is 0.33 of having restless leg syndrome, while for people without fibromyalgia, the probability is 0.03. About 2% of the population has fibromyalgia. Create a tree diagram from this information and use it to find the probability that a person with restless leg syndrome has fibromyalgia.

Answers

Answer:

The probability that a person with restless leg syndrome has fibromyalgia is 0.183.

Step-by-step explanation:

Denote the events as follows:

F = a person with fibromyalgia

R = a person having restless leg syndrome

The information provided is as follows:

P (R | F) = 0.33

P (R | F') = 0.03

P (F) = 0.02

Consider the tree diagram attached below.

Compute the probability that a person with restless leg syndrome has fibromyalgia as follows:

[tex]P(F|R)=\frac{P(R|F)P(F)}{P(R|F)P(F)+P(R|F')P(F')}[/tex]

            [tex]=\frac{(0.33\times 0.02)}{(0.33\times 0.02)+(0.03\times 0.98)}\\\\=\frac{0.0066}{0.0066+0.0294}\\\\=0.183333\\\\\approx 0.183[/tex]

Thus, the probability that a person with restless leg syndrome has fibromyalgia is 0.183.

Please someone explain how to solve for x.

Answers

Answer:

x =30

Step-by-step explanation:

We can use ratios to solve

18            20

--------- = ----------

18+27      20+x

Simplify

18            20

--------- = ----------

45         20+x

Using cross products

18 *(20+x) = 20*45

18 ( 20+x) = 900

Divide each side by 18

18 /18*(20+x) = 900/18

20+x =50

Subtract 20 from each side

20+x-20 = 50-20

x=30

Answer:

30

Step-by-step explanation:

to solve this type of problem you need to cross multiply.So you get the pairs which are 18 and 20 and 27 and x so the equation looks like 18/20=27/x so 18 times x is 18x and 20 times 27 is 540 so the equation is now 18c=540 then you divide both sides by 18 so x will be isolated which means x will be by itself so 18x divided by 18 is x and 540 divided by 18 is 30 so the equation is now x=30

Check the statements that are true.
A. An arithmetic sequence is a linear function whose domain is restricted to the set of non-negative integers.
B. A geometric sequence is a linear function whose domain is restricted to the set of non-negative integers.
C. An arithmetic sequence is an exponential function whose domain is restricted to the set of non-negative integers.
D. A geometric sequence is an exponential function whose domain is restricted to the set of non-negative integers.

Answers

Answer:

A and D.  

Step-by-step explanation:

A sequence is a set of the objects or numbers in a specific order. It is a function whose domain is a set of natural numbers or non-negative integers i.e. {1, 2, 3,..}

(A)

"An arithmetic sequence is a linear function whose domain is restricted to the set of non-negative integers."  

The general form an arithmetic sequence is:

[tex]a_{n}=a_{1}+(n-1)d[/tex]

The function is linear. The sequence consists of either numbers that are increasing or decreasing based on the value of d, the common difference.

So, the statement provided is True.

(D)

"A geometric sequence is an exponential function whose domain is restricted to the set of non-negative integers."

The general form an geometric sequence is:

[tex]a_{n}=a_{1}\cdot r^{n-1}[/tex]

The function is exponential. The sequence consists of either numbers that are exponentially increasing or decreasing by the factor r, the common ratio.

So, the statement provided is True.

wilma buys a new game that is priced at 43.89. She gets successive discounts of 15% followed by 5% off on the game. The purchase price of Wilma's game is what percentage of the original price?

Answers

Answer:

C

Step-by-step explanation:

Edge 2020

Answer:

c edg

Step-by-step explanation:

Chris has 12 sweets. He has 3 red, 6 blue, 1 yellow and 2 green sweets what fraction of his sweets is red

Answers

Answer:

He has had a quarter of the red one

Step-by-step explanation:

3/12 is 1/4 when simplified

1/4 you just need to simplify 3/12

Let f(x) = 5^x Find f(-3).

what did you guys get?

Answers

Answer:

I got 1/125

Step-by-step explanation:

Which expression shows the COMMUTATIVE PROPERTY of addition?
A. 3 + 5 + 2 = 3 + (5 + 2)
B. 3 + 5 + 2 = 8 + 2
C. 3 + 5 + 2 = 5 + 2 + 3
D. 3 + 5 + 2 = 10

Answers

Answer:

C

Step-by-step explanation:

Commutative property means to add in a different order.

The point-slope form of the equation of the line that passes through (-4, -3) and (12, 1) is y-1 =1/4 (x – 12). What
is the standard form of the equation for this line?

Answers

Answer: y=1/4x - 2

Step-by-step explanation: The easiest way to solve this would be to graph it in point-slope form then find the slope and y-intercepts. Try using desmos for that method. There are multiple ways to convert point-slope to standard, however, and I would suggest talking to your teacher to see which method s/he prefers you use. Let me know, and I can help you more if you need it.

Hope this helps,

Lacia :))

Which transformation of a shape may result in a new shape not congruent with the original shape?
O dilation
O reflection
O rotation
O translation

Answers

Answer:

dilation

Step-by-step explanation:

dilation will make the shape larger or smaller which will change the shape.

HELP PLSSS . Miley is purchasing several yards of fabric for a school project. If she spent $13.41 and the fabric was $2.98 per yard, how many yards did she purchase?

Answers

Answer:

4.5 yards of fabric.

Step-by-step explanation:

In order to find out how many yards she purchased, you need to divide the money she spent by the price of fabric per yard. Therefore, you divide

13.41/2.98=4.5

4.5 yards of fabric

Terminating vs. Repeating
Some rational number, such as 1/2, 3/8, and 2/5 have a finite
decimal (terminating decimal); while others, such as 1/3, have
infinite decimal representation (repeating decimal).
For which positive whole numbers, n, is the decimal
representation of 1/n finite? For which is it infinite? Describe
the pattern, if there is one.

Answers

thats uhm hard how u do that

Answer:

If the positive whole number is a multiple of 3, one divided by that number will always be a non-terminating decimal.

Find the volume of the solid under the plane 3x + 5y − z = 0 and above the region bounded by y = x and y = x4.

Answers

Answer:

13/18

Step-by-step explanation:

See attachment

2^4x4^4=2^4x2^n=2^12

Answers

Answer:

don''t knw

Step-by-step explanation:

A food-protection agency counts the number of insect heads found per 100-gram batch of wheat flour. The researchers have 500 batches, and they want to know whether the frequency of insect heads in batches follows a distribution called a Poisson distribution. To generate the expected frequencies of batches with different numbers of insect heads under a Poisson distribution, they had to estimate the mean number of insect heads per batch from the data. The 500 batches included at least 5 batches having 0, 1, 2, 3, or 4 insect heads. No batches had more than four heads. Given this information, there are_____classes (k).

Answers

Answer:

The correct answer is k = 5.

Step-by-step explanation:

The Chi-square goodness of fit test would be used to determine whether the frequency of insect heads in batches follows a distribution called a Poisson distribution.

The hypothesis for the test can be defined as follows:

H₀: The frequency of insect heads in batches does not follows a Poisson distribution.

Hₐ: The frequency of insect heads in batches follows a Poisson distribution.

Assume that the significance level of the test is, α = 0.05.

The Chi-square test statistic is given by:

[tex]\chi^{2}=\sum\limits^{k}_{i=1}\frac{(O_{i}-E_{i})^{2}}{E_{i}}[/tex]

It is provided that the 500 batches included at least 5 batches having 0, 1, 2, 3, or 4 insect heads. No batches had more than four heads.

So, the number of classes or categories are, k = 5.

Thus, the correct answer is k = 5.

Where do you put the parentheses in this equation
9+5÷5+2
Value:2

I am not good at math and this is for my 5th grader

Answers

Answer:

here we go.....

Step-by-step explanation:

9+5 equals14 5 +2 equals 7

14 divided by 7 equals 2

hope you get it correct

Need Help. ( Look at the picture). Will Mark Brainliest. Graph the step function over the interval. And you can just write the steps out also. Working on it now but really need help please asap. ​

Answers

Answer:

x = -3

Step-by-step explanation:

f(x) = x + 3

0 = x + 3

-x = 3

x = -3

Please help me, I am sorry that I’m so terrible at math

Answers

Answer:

x[tex]\leq[/tex]3

Step-by-step explanation:

hope this helps

Answer:

-6 <x< 3 or x<3, x<-6

Step-by-step explanation:

-18 < 4x +6 < 18

-18-6 <4x< 18-6

-24 <4x< 12

-24/4 <x< 12/4

-6 <x< 3

hope this help you

grrrrrr please help i’ll give u a cookie :)

Answers

im only in 6th grade

Step-by-step explanation:

I will give you 25 points help please

Answers

Answer:

horizontal 2 units to the right, vertical translation 3 units up, vertical stretch by a factor of 4

Need a step by step answer please

Answers

Answer:

x=10

Step-by-step explanation:

x+2+x=22

combine like terms x + x to get 2x:

2x + 2 = 22

subtract 2 on both sides:

2x = 20

divide by 2 on both sides to isolate x:

x=10

g(x)=x^3
f(x)=(x+6)^3 -3
Ring to the equations above the graph of f(x) would be obtained from the graph of g(x) by translating the graph of g(x)

Answers

A, left 6 Units and down 3 units

Hope this helps

one fourth of a number is 12 find the number​

Answers

pretty sure it’s 3. if you multiply .25

Answer:

48

Step-by-step explanation:

If 12 is one-fourth of a number, just multiply 12 by four to find the whole number.

12 x 4 = 48

You could have also set this up as an equation

12 = 1/4x

And then divide 12 by one-fourth

12/(1/4) = 48

A student takes a multiple-choice test that has 10 questions. Each question has four choices. The student guesses randomly at each answer. Let X be the number of questions the student gets correct. (a) Find P(X = 3). (b) Find P(X > 2). (c) To pass the test, the student must answer 7 or more questions correctly. Would it be unusual for the student to pass? Explain.

Answers

Answer:

1)0.2502

2)0.475

3)0.003505

Step-by-step explanation:

Total No. of question n= 10

There are four choices in each question

So, Probability of success [tex]p = \frac{1}{4}[/tex]

Probability of failure q  = [tex]1- \frac{1}{4}=\frac{3}{4}[/tex]

We will use binomial over here

[tex]P(X=x)=^nC_r p^r q^{n-r}[/tex]

1)

[tex]P(X = 3)=^{10}C_3 (\frac{1}{4})^3 (\frac{3}{4})^7\\P(X = 3)=\frac{10!}{3!7!} (\frac{1}{4})^3 (\frac{3}{4})^7\\P(X = 3)=0.2502[/tex]

2)  [tex]P(X > 2)=1-P(X\leq 2)[/tex]

P(X>2)=1-(P(X=0)+P(X=1)+P(X=2))

[tex]P(X>2)=1-(^{10}C_0 (\frac{1}{4})^0 (\frac{3}{4})^{10}+(^{10}C_1 (\frac{1}{4})^1 (\frac{3}{4})^9+^{10}C_2 (\frac{1}{4})^2 (\frac{3}{4})^8)[/tex]

[tex]P(X>2)=1-((\frac{1}{4})^0 (\frac{3}{4})^{10}+(\frac{10!}{1!9!} (\frac{1}{4})^1 (\frac{3}{4})^9+\frac{10!}{2!8!} (\frac{1}{4})^2 (\frac{3}{4})^8)[/tex]

P(X>2)=0.475

3)

[tex]P(X\geq 7)=P(X=7)+P(X=8)+P(X=9)+P(X=10)\\\\P(X\geq 7)=^{10}C_7 (\frac{1}{4})^7 (\frac{3}{4})^{3}+(^{10}C_8 (\frac{1}{4})^8 (\frac{3}{4})^2+^{10}C_9 (\frac{1}{4})^9 (\frac{3}{4})^1+^{10}C_{10} (\frac{1}{4})^{10} (\frac{3}{4})^0\\\\P(X\geq 7)=\frac{10!}{7!3!} (\frac{1}{4})^7 (\frac{3}{4})^{3}+\frac{10!}{8!2!} (\frac{1}{4})^8 (\frac{3}{4})^2+\frac{10!}{9!1!} (\frac{1}{4})^9 (\frac{3}{4})^1+\frac{10!}{10!0!}(\frac{1}{4})^{10} (\frac{3}{4})^0\\\\P(X\geq 7)=0.003505[/tex]

the sum of a interior angle measures of a polygon is 5220. How many sides does the polygon have

Answers

9514 1404 393

Answer:

  31

Step-by-step explanation:

The relationship between sides and the sum of angles is ...

  sum of angles = (sides - 2)·180°

Filling in the given value and solving for "sides", we get ...

  5220 = (sides -2)180

  29 = sides -2 . . . . . . . . . divide by 180

  31 = sides . . . . . . . . . . . . add 2

The polygon has 31 sides.

Answer:

31

Step-by-step explanation:

5220/180=29+2=31

a cylinder made of metal has radius of 18 cm and height 40 cm if melted how many smaller cylinders of radius 2 cm and height 5 cm can be made

Answers

Answer:

648

Step-by-step explanation:

Volume of a cylinder =Pi× r²×h

volume of the cylinder before melted

v=Pi×18²×40

v=40715.04cm³

Volume of the smaller cylinder

v=Pi×2²×5

v=62.83

40715.04÷62.83

=648.019

=648 small cylinder can be made

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