(Hat Check problem). n people enter the restaurant and put their hats at the reception. Each person gets a random hat back when going back after having dinner. Find the expected value and variance of the number of people who get their right hat back.

Answers

Answer 1

Answer:

E[X] = 1

Var[X] = 1

Step-by-step explanation:

We are told that n people enter the restaurant and put their hats at the reception.

This means that there are n hats.

Also, we are told that eeach person gets a random hat back when going back after having dinner.

Thus, each person will pick a hat uniformly at random and will get a right hat back with the probability: 1/n.

The expectation is linear even though the random variables are dependent. Thus, the expected mean of the total number of persons who get their right hat back is: E[X] = n × 1/n = 1

Now, the variance in hat problem is given by;

Var[X] = E[X²] - E[X]²

This gives;

Var[X] = E[X²] - 1

Now, E[X²] is expressed as;

E[X²] = n(1/n) + n(n - 1)•(1/n)•(1/(n - 1))

E[X²] = 1 + 1

E[X²] = 2

Thus;

Var[X] = 2 - 1

Var[X] = 1


Related Questions

Using a table, show 60% of 80 60% of 80 is о​

Answers

You have 80 pens for example, and it's all what you have, so it's 100% of your owns; you used 20 and still 60 and you want to find he percentage of what it rest! So you make 100% _______80 X _______60 you will have 100% * 60 = X * 80 so X = 100% * 60/ 80 X= 75%

12 time 10 times 10 times 10

Answers

Answer:i used a calculator 12000

Step-by-step explanation:12 × 10 × 10 × 10 = 12000

and have a nice Day :)

Answer:

12000

Step-by-step explanation:

If you multiply 12 by 10 its 120, if you add 2 more 0's to the end of the number, it will be 12000, so, basically, any time you multiply a number by 10, you add a 0 to the end of the number your multiplying 10 by, hope this helps:)

what is the solution to this equation: 5x to the 2 power - 36x - 81 = ?

Answers

Answer:

5x² - 36x - 81

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Algebra I

Combining Like TermsStandard Form: ax² + bx + c = 0

Step-by-step explanation:

Step 1: Define expression

5x² - 36x - 81

Step 2: Simplify

We cannot simplify the expression down further.

Which operation will not change the value of any nonzero number?

Answers

flipAnswer:

Multiplication

Step-by-step explanation:

The answer is multiplication because the multiplication by two will definetly flip the value of any sort of number that is non zero.

Decide what can be used to determine the equation of a line when you have two points, but no slope.
a.
slope-intercept form
c.
point-slope form
b.
general form
d.
slope formula, then use one of the given points to find the equation

Answers

Answer:

Slope formula!

Step-by-step explanation:

You'd use that to find the slope!! THEN you'd use slope intercept form, but this one first!

I really hope this helped!! Have a good day :)

Dentro de 11 años la edad de Vicente será la mitad del cuadrado de la edad que tenía hace 13 años. ¿Qué edad tiene Vicente ahora?.

Answers

La respuesta ceria 12

PLZ PLZ PLZ HELP ME GET THIS RIGHT ILL GIVE 40 POINTS AND BRAINLY IF THERE BOTH RIGHT, I REALLY NEED HELP I SUCK AT GEOMETRY!!!

Answers

I believe they are both 120

Suppose z is a complex number (a point in the plane) with angle 30 degrees and radius 2. Suppose w is a complex number with angle 60 degrees and radius 5. If z and w are multiplied together the angle of their product is how many degrees?

Answer value

Answers

Write each number in complex polar form:

[tex]z=2e^{i\cdot30^\circ}[/tex]

[tex]w=5e^{i\cdot60^\circ}[/tex]

When you multiply two exponential expression with the same base (here, that's e), you end up adding the exponents, so that

[tex]zw=(2\cdot5)e^{i\cdot30^\circ+i\cdot60^\circ}=10e^{i\cdot90^\circ}=10i[/tex]

so the angle of the product zw is 90°.

Place the following fractions and decimals in order from least to greatest:
12/5
3 1/3
3 1/6
3.09

Answers

Answer:

.09,1/6,1/3,2/5

Step-by-step explanation:

Answer: 12/5, 3.09, 3 and 1/6, 3 and 1/3

Step-by-step explanation: 12/5 is only equal to 2.4, so thats smallest. 3.09 is smaller compared to fractions.

tip: the bigger the bottom number on a fraction is, the smaller the number is. ex: 1/5 is actually a bigger number than 1/10

The current population of a small town is 10,500, and its population is expected to grow at a rate of 5% per year. Which of the following functions represents the expected population of the town, where t is the number of years that have passed since the current year?

Answers

Answer:

f(x) = 10,500 x 1.05^t

$1,400 principal earning 6%, compounded semi-annually, after 10 years

Answers

Answer: $2528.56  is the answer because if you do the problem you should get something like this

A=P(1+r/n)^nt

Plug in the values:

P=1400, r=6/100=0.6,

n=2 and t=10

A=1400(1+.06/2)^2(10)

A=$2528.56

Hope it helped

Yours,

Nathaniel

Step-by-step explanation:

5. Maria is tracking the number of miles she runs in one week. She is using the track at her

school, which measures in meters.

Part A; if Maria runs 5.000 meters each week, how many miles does she rung Round your

answer to the nearest tenth. (1 meter = 1.09361 yards)

Answers

Answer:

0.00310 miles

Step-by-step explanation:

Maria runs 5 m each week. We need to find how miles she run. It means we need to convert meters to miles. The relation between meter and yards is as follows :

1 meter = 1.09361 yards

Also, 1 mile = 1760 yards

It means,

1 mile = 1609.34 m

1 m = (1/1609.34) miles

[tex]5\ m=\dfrac{5}{1609.34}\ \text{miles}\\\\=0.00310\ \text{miles}[/tex]

So, she will cover 0.00310 miles.

APQR is an equilateral triangle. One side measures 5x - 7 and another side 3x + 11. Find the length of each
side.

Answers

Step-by-step explanation:

x=9

therefore,

each sides length is 9

5x-7=3x+11

=5x-3x=7+11

=2x=18

=x=9

See the attachment plsss

Glenda placed $1900 in a savings account which compounds interest continuously at a rate of 2.4%. How much will she have in the account after 2 years?

Answers

Answer: $1,992

Step-by-step explanation: :)

Let the function f be defined by f(x) = 12 -5x


4. Is it true that f(0) = 0?


5. Explain why or why not?

ILL MARK YOU BRAINLIEST if you answer xx

Answers

4. It is not true
5. This is because if you substitute f(0) the equation would be f(x) = 12-0 or f(x) = 12
Hope this helps, if it does can I get brainliest ?

HELP please, see the picture below thank you.
I have a test, please

Answers

5(1 - 2g + 4h)
5 - 10g + 20h

Answer:

5 - 10g + 20b

Step-by-step explanation:

(5 times 1) plus (5 times -3g)  plus (5 times 4h)

5 - 10g + 20h.

This is the answer.

#teamtrees #WAP (Water And Plant)

A crew of highway workers paved 1/5 mile in 1/8 hour. If they work at the same rate, how much will they pave in one hour?

Answers

Answer:37.5

Step-by-step explanation:

The work a crew will pave in an hour will be 8/5 miles.

What is an expression?

The mathematical expression combines numerical variables and operations denoted by addition, subtraction, multiplication, and division signs.

Mathematical symbols can be used to represent numbers (constants), variables, operations, functions, brackets, punctuation, and grouping. They can also denote the logical syntax's operation order and other properties.

Given that a crew of highway workers paved 1/5 mile in 1/8 hour. The amount of work will be calculated as,

1 / 8 hours ⇒ 1 / 5 miles

1 hour ⇒ 8 x (1 / 5 ) miles

1 hour ⇒ 8 / 5 miles

Therefore, the work a crew will pave in an hour will be 8/5 miles.

To know more about an expression follow

https://brainly.com/question/16174575

#SPJ2

2. What is the mass of an object that is 10 m above the ground and has
543 J of PE?

Answers

PE = mgh
Plug in the values
543 J = m * 9.8 * 10
543 = m * 98
Divide both sides by 98
m = 5.54 kg

What is the reciprocal of 8 5/6​

Answers

475).)ggbbghffffrrffffffffffffffffff

What is the slope of the line that contains these points?

Answers

Answer:

[tex]m=-7[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Algebra I

Slope Formula: [tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]

Step-by-step explanation:

Step 1: Define

Find points from chart.

Point (39, 36)

Point (40, 29)

Step 2: Find slope m

Substitute:                    [tex]m=\frac{29-36}{40-39}[/tex]Subtract:                       [tex]m=\frac{-7}{1}[/tex]Divide:                          [tex]m=-7[/tex]
(Y2-y1)/(x2-x1) slope formula
Pick any two points: (39,36), (40,29)
(29-36)/(40-39) = -7/1 = -7
The slope is -7

What is the slope of points M(1, 3) and N(5,0) ? Help

Answers

Answer:

-3/4

Step-by-step explanation:

Line is passing through the points [tex] M(1,\:3)=(x_1, \: y_1) \: \&\: N(5, \: 0)=(x_2,\:y_2) [/tex]

Slope of MN

[tex] = \frac{y_2 - y_1}{x_2 - x_1} \\ \\ = \frac{0 - 3}{5 - 1} \\ \\ = \frac{ - 3}{4} \\ \\ = - \frac{3}{4} [/tex]

421.2 - 305.8
Using mental math

Answers

Answer:

114.4

Step-by-step explanation:

421.2

-305.2

114.4

In a five-card poker hand, what is the probability of being dealt exactly one nine and no picture cards?

Answers

Answer:

0.0907

Step-by-step explanation:

There are 12 picture cards

There are 4 9's

There are 52-12-4 = 36 cards that are not 9's and not picture cards

(5*58905)/(52C5)

it is urgent.so anyone solve this

Answers

Answer:

Step-by-step explanation:

Answer:

1i.) x = 18

1ii.) x = 40

2.) x = 155

3i.) ABD = 115° (actually this is wrong, idk how to calculate this ;-;

3ii.) BEF = 135°

Step-by-step explanation:

*All triangles add up to 180° in total of all angles added together*

i.) Find x

4x + 3x + 3x = 180°

10x = 180°

10x/10 = 180/10

x = 18

----------------------------------------

ii.) Find x

180 - 115 = 65

65° + 75° + x° = 180°

140° + x° = 180°

x° = 180° - 140°

x = 40°

----------------------------------------

2.) Find x

180 - 145 = 35

45° + 35° + n° = 180°

80° + n° = 180°

n° = 180° - 80°

n° = 100°

*Vertical Angles of n and m (variables I randomly made so I can solve this), so they are both the same*

100 + 55 + m = 180

155 + m = 180

m = 180 - 155

m = 25

25 + x = 180

x = 180 - 25

x = 155

----------------------------------------

3.) Find Angles

i.) ABD

180° - 65° = 115°

Angle ABD = 115°

ii.) BEF

180° - 110° = 70°

70° + 65° + x° = 180

135° + x° = 180°

x° = 180° - 135°

x = 45°

180° - 45° = 135°

Angle BEF = 135°

3.
Determine the amplitude (A), period (P) and phase shift (PS) of the function
f(x) = tan (2x + 1).
A = 1, p = ,PS = (2:0)
A = 1, P = 27, PS =
o
s = (2)
A = 1, p = 5, P = (1,0).
A = 1, P = 2.PS = (6, 1)

Answers

Answer:

for f(x)=tan(2x+1)

Amplitude: None

Period: pi/2

phase Shift: -1/2(1/2 to the left)

Find the simple interest and the total amount after three years.
Principal = 7800 rupees
Annual rate of interest = 9.5%
Total interest =____rupees
Total amount =____rupees

Answers

Answer:

[tex] \boxed{ \sf{Total \:Interest = \underline{ 2223} \: rupees}}[/tex]

[tex] \boxed{ \sf{Total \: Amount = \underline{10023} \: rupees}} [/tex]

Step-by-step explanation:

♨ Given :Principal ( P ) = 7800 rupeesAnnual rate of interest ( R ) = 9.5 %Time ( T ) = 3 years

♨ To find :Total interest ( I ) = ?Total amount ( A ) = ?

Finding the total interest :

[tex] \boxed{ \sf{Simple \: interest \: ( \: I\: )\: = \frac{Principal \: ( \: P \: ) \: \times \: Time \: ( \: T \: ) \: \times \: Rate \: ( \: R \: )}{100}}} [/tex]

[tex] \longrightarrow{ \sf{ \frac{7800 \times 3 \times 9.5}{100}}} [/tex]

[tex] \longrightarrow{ \sf{ \frac{222300}{100}}} [/tex]

[tex] \longrightarrow{ \sf{2223 \: rupees}}[/tex]

The total interest = 2223 rupees.

✎ Finding the total Amount :

[tex] \boxed{ \sf{Amount \: (A) = Principal \: ( \: P \: ) \: + \: Interest \: ( \: I \: )}}[/tex]

[tex] \longrightarrow{ \sf{7800 \: rupees + 2223 \: rupees}}[/tex]

[tex] \longrightarrow{ \sf{10023 \: rupees}}[/tex]

The total amount = 10023 rupees.

--------------------------------------------------------------

☞ Additional Info :Principal : The money which is borrowed or deposited is called principal ( P ).Interest : The additional amount of money which is paid by borrower to the lender is called Interest ( I ) .Time : The duration of time for which principal is deposited or borrowed is termed as time period ( T ).Rate : The condition under which the interest is charged is called rate ( R ).Amount : The sum of principal and interest is called an amount ( A ).

✑ Important Formulaes :[tex] \sf{Interest \: = \frac{Principal \times Time \times Rate}{100}} [/tex]

[tex] \sf{Principal = \frac{Interest \: \times \: 100}{Time \times Rate}} [/tex]

[tex] \sf{Time = \frac{Interest \: \times \: 100}{Principal \times Rate}} [/tex]

[tex] \sf{Rate = \frac{Interest \: \times \: 100}{Principal \times Time}} [/tex]

[tex] \sf{Amount = Principal + Interest}[/tex]

[tex] \sf{Principal = Amount - Interest}[/tex]

[tex] \sf{Interest = Amount - Principal}[/tex]

Hope I helped!

Have a wonderful time ツ

~TheAnimeGirl

16.9 and 1.7 and 0.17 and 2.0 least to greatest

Answers

Answer:

0.17,1.7,2.0,16.9

Step-by-step explanation:

Answer:

0.17    1.7    2.0    16.9

Step-by-step explanation:

your going to look at the first number

An experiment requires a sequence of three steps. The first step can result in six possible outcomes, the second in three possible outcomes, and the third in four possible outcomes. What is the total number of outcomes possible?

Answers

Answer:

72

Step-by-step explanation:

The total no of outcomes of an experiment is given by :

N = n₁× n₂ ×n₃ ×....

Where,

n₁,n₂,n₃... are possible outcomes in step 1,2,3 and so on

In this problem, there are 3 steps.

n₁ = 6, n₂ = 3, n₃ = 4

Total number of possible outcomes = 6(3)(4) = 72

Hence, there are 72 possible outcomes.

102,918,029 Plus 16/3

Answers

Answer:

102,918,0343.3

Step-by-step explanation:

tbh idek if this is right :|

Answer:

ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh hmmmmmmmmmm i think carrot

Step-by-step explanation:

Do you guys know this

Answers

Answer && Step-by-step explanation:

Simple plug and chug

we know a+b == 6 so replace the set as 6 so:

2(6)+6/6+(6)^2-2

12+1+36-2

49-2

==47

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