Exercise 3.62. A little boy plays outside in the yard. On his own he would come back inside at a random time uniformly distributed on the interval [0, 1]. (Let us take the units to be hours.) However, if the boy is not back inside in 45 minutes his mother brings him in. Let X be the time when the boy comes back inside (a) Find the cumulative distribution function F of X (b) Find the mean E(X) (c) Find the variance Var(X) Hint. You should see something analogous in Examples 3.20 and 3.38.

Answers

Answer 1

a) The cumulative distribution function F of X is: F(x) = P(X ≤ x) = 1

b) The mean E(X) is: E(X) = 0.5 hours.

c) The variance Var(X) is: the variance of X is approximately 0.0833 hours².

To find the cumulative distribution function (CDF) of X, we need to consider two cases: when the boy comes back inside before 45 minutes and when the boy is brought inside by his mother after 45 minutes.

(a) Cumulative Distribution Function (CDF) F of X:

For 0 ≤ x < 0.75 (when the boy comes back inside before 45 minutes):

Since the boy comes back inside uniformly distributed on the interval [0, 1], the CDF is simply the probability that the boy comes back inside before time x.

The probability of the boy coming back inside before x is equal to x, as it is a uniform distribution.

F(x) = P(X ≤ x) = x

For 0.75 ≤ x ≤ 1 (when the mother brings the boy inside after 45 minutes):

If the boy is not back inside at 45 minutes (0.75 hours), his mother brings him inside.

Therefore, the probability of the boy coming back inside before x in this case is 1.

F(x) = P(X ≤ x) = 1

(b) Mean (Expected Value) E(X):

The expected value of X, denoted by E(X), is the average time the boy spends outside before coming back inside.

For a uniform distribution on the interval [0, 1], the expected value is the midpoint of the interval.

Therefore, E(X) = (1 + 0) / 2 = 0.5 hours.

(c) Variance Var(X):

The variance of X, denoted by Var(X), measures the spread or variability of the random variable X around its mean.

For a uniform distribution on the interval [0, 1], the variance is given by:

Var(X) = (1² - 0²) / 12 = 1 / 12 ≈ 0.0833 hours²

So, the variance of X is approximately 0.0833 hours².

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Related Questions

A particle moves along a horizontal line so that its position at time t, t ≥ 0, is given by
s(t) = 40 + te^−t/20.
Find the minimum velocity of the particle for 0 ≤ t ≤ 100.

Answers

Answer:

The minimum velocity of the particle  = [tex]-e^{-2 }[/tex] units

Step-by-step explanation:

Given - A particle moves along a horizontal line so that its position at time t,

t ≥ 0, is given by  s(t) = 40 + te^−t/20.

To find - Find the minimum velocity of the particle for 0 ≤ t ≤ 100.

Proof -

Velocity, v(t)  = [tex]\frac{d}{dt}(40 + te^{-\frac{t}{20} } )[/tex]

Now,

[tex]\frac{d}{dt}(40 + te^{-\frac{t}{20} } )[/tex] =  [tex]\frac{d}{dt}(40 ) + \frac{d}{dt}(te^{-\frac{t}{20} } )[/tex]

                       = 0 + [tex]t\frac{d}{dt}(e^{-\frac{t}{20} } ) + e^{-\frac{t}{20} }\frac{d}{dt}(t )[/tex]

                       = [tex]t(-\frac{1}{20} )e^{-\frac{t}{20} } + e^{-\frac{t}{20} }[/tex]

⇒v(t) = [tex]-\frac{t}{20}e^{-\frac{t}{20} } + e^{-\frac{t}{20} }[/tex]

Now,

For minimum velocity, Put [tex]\frac{d}{dt}(v(t)) = 0[/tex]

Now,

[tex]\frac{d}{dt}[v(t)] = \frac{d}{dt} [ -\frac{t}{20}e^{-\frac{t}{20} } + e^{-\frac{t}{20} } ][/tex]

           = [tex]-\frac{2}{20} e^{-\frac{t}{20} } + \frac{t}{400} e^{-\frac{t}{20} }[/tex]

Now,

Put [tex]\frac{d}{dt}(v(t)) = 0[/tex], we get

[tex]-\frac{2}{20} = - \frac{t}{400}[/tex]

⇒t = 40

Now,

Check that the point is minimum or maximum

Calculate  [tex]\frac{d^{2} }{dt^{2} } [v(t)][/tex]

Now,

[tex]\frac{d^{2} }{dt^{2} } [v(t)][/tex] = [tex]\frac{d}{dt} [ -\frac{2}{20} e^{-\frac{t}{20} } + \frac{t}{400} e^{-\frac{t}{20} }][/tex]

            = [tex]\frac{1}{400}e^{- \frac{t}{20} } [ 3 - \frac{t}{20}][/tex]

⇒[tex]\frac{d^{2} }{dt^{2} } [v(t)][/tex]  = [tex]\frac{1}{400}e^{- \frac{t}{20} } [ 3 - \frac{t}{20}][/tex]  > 0

∴ we get

t = 40 is point of minimum

So,

The minimum velocity be

v(40) = [tex]-\frac{40}{20}e^{-\frac{40}{20} } + e^{-\frac{40}{20} }[/tex]

      = [tex]-2e^{-2 } + e^{-2 }[/tex]

      = [tex]-e^{-2 }[/tex]

⇒v(40) = [tex]-e^{-2 }[/tex] units

∴ we get

The minimum velocity of the particle  = [tex]-e^{-2 }[/tex] units

down the additive inverse of 4 by 7​

Answers

Answer:

[tex] \color{magenta} \huge{ \boxed{answer}}[/tex]

The additive inverse of 4/7 is -4/7.

hopefully help:)

Step-by-step explanation:

#CarryOnLearning

Which transformation could NOT be used to prove that two circles are congruent to one another?
a dilation with a scale factor of 2
a dilation with a scale factor of 1
a reflection
a rotation

Answers

Answer:

the congruent the congruent???

Step-by-step explanation:a dilation a dilation with two factors???

The transformation which could not be used to prove that two circles are congruent to one another is dilation with a scale factor of 2.

Option A is the correct answer.

What is a circle?

A circle is a two-dimensional figure with a radius and circumference of 2πr.

We have,

Dilation:

It changes the size of the figure so, the transformed figure is not congruent with the original figure.

Scale factor = 1 will not change the size of the figure.

Scale factor = 2 will change the size of the figure.

Reflection:

It does not change the size or the shape.

Rotation:

It does not change the size or the shape.

Thus,

The transformation of dilation with a scale factor of 2 could not be used to prove that two circles are congruent to one another.

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Felicia and gabriella are on the hamilton middle school basketball team. The box plots show the number of points they scored in 8 basketball games.

Answers

Answer:

I

Step-by-step explanation:

I need the box plot to do the problem

Melinda and Davy are making postcards to announce their new address. The table shows the number of postcards they can make together during each hour they are working. If they continue to make postcards at this rate, what is the total number they will make in 6 hours? Postcards
Number of Hours Number of Postcards
1 7
2 14
3 21

Answers

Answer:

3

Step-by-step explanation:


The sides of the figure below measure 11, 22, and 27 meters. Find the perimeter. Do not include units in your answer

Answers

Answer:

27

Step-by-step explanation:

try that it should work for their

The perimeter of the figure is 60

How to determine the perimeter?

The side lengths are given as:

11, 22, and 27 meters

The perimeter of the triangle is the sum of its side length.

So, we have:

Perimeter = 11 + 22 + 27

Evaluate the sum

Perimeter = 60

Hence, the perimeter of the figure is 60

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What would you call the expression 2x -5y - 7?

Answers

Answer:

Trinomial

Step-by-step explanation:

Its called a Trinomial since it has 3 terms in it                                                                                                                                

Hope its helps!

Can someone please help!!!

Answers

Answer:

its the 3rd one

Step-by-step explanation:

anime recommendations

Answers

Answer:

what genre babe‍♀️

Answer:

It depends on a lot what kind you like and if u have watched a lot

the promised Neverland

Black Clover

Aot

HxH

Monster

Code grass

The classroom of the elite

Psycho pass season 1 only

COMEDY

The disastrous life of saiki k

Kaguya sama love is war

I need help and I don’t know how to check it

Answers

Answer:

y=2x+3

Step-by-step explanation:

cuánto es 567 + 678 es igual

Answers

Answer: 1245 :)

Step-by-step explanation:

Answer:

la respuesta es 1245

567+678=1245

Use a double number line to answer Problem 1-5.


Tanner collected 360 cans and bottle while fundraising for his baseball team. This eas 40% of what Reggie collected. How many cans and bottles dif Reggie collect?​

Answers

Answer:

900 cans and bottles.

Hope that helps!

Step-by-step explanation:

360 / 4 = 90

90 x 100 = 900

Hope that helps!

HELPPPPP PLSSSSSS !!!!!!!


Charmaine is having a party. She'll have 4 tables for every 8 guests. Complete the table below showing the number of tables and the number of guests​

Answers

Answer:

Top is 18, Bottom goes 6 for 12, then 7 for 14, then 10 for 20

Step-by-step explanation:

2 guests = 1 table

Divide 8 and 4
Which would be 2 so 2 people for table

What is the number?
Help me

Answers

It is 238 that is not the answer so yea

The shorter leg of a right triangle is 10 meters. the hypotenuse is 2 meters longer than the longer leg. Find all three sides

Answers

Answer:

the shorter leg is 10 meters, longer leg is 24 meters and the hypotenuse is 26 meters

5. Can two fractions point to the same location on the number line? Explain.

Answers

Answer:

1 2 = 2 4 = 3 6 = 4 8 = etc. All of these fractions are located at the same point on the number line. Therefore, they represent the same number. From the paper folding exercises, we see that increasing both numerator and denominator of a fraction by the same factor gives an equivalent or equal fraction.

Hope this helps :) Just know I tried.

Please help!!! I'm very confused! Im giving points for it but if please tell the truth <3

Answers

Answer:

A

Step-by-step explanation:

It actually trying to trick you with a double negative

Answer:

A

Step-by-step explanation:

Squares do have right angles, if they did not have to then all other ssquares with no right angles would be considered rhombuses.

The question is sking which does not apply, a does not apply but thats what theyre asking so its a

Function lis defined by the equation r
R=5/8t - 9

Function 2 is defined by the following table,
I
Which function has a greater y-intercept?

Answers

Answer:

Both have the same y-intercept (-9)

Step-by-step explanation:

✔️Function 1, r = ⅝t - 9, is given in the slope-intercept form, y = mx + b.

b = y-intercept = -9

y-intercept for Function 1 = -9

✔️Function 2, using the table given, the y-intercept is the value of r when t = 0.

Thus, r = -9 when t = 0.

y-intercept for Function 2 = -9

✔️Both functions has the same y-intercept. None is greater than the other.

Determine the slope of the line whose equation is 2x-3y=5

Answers

The slope would be 2/3 I hope this helps you out!

Can someone help quick please

Answers

Answer:

PC = 4 cm

Step-by-step explanation:

AP = 4 cm

Because AB = BC, PB = PB, and we know that angle PBA = 90 degrees: triangle PBA is congruent to triangle PBC by the Side-Angle-Side theorem.

PC = AP because corresponding parts of congruent triangles are congruent.

Which table of ordered pairs represents a proportional relationship? I’m a timer please hurry thank you so much
х
-3
-4
-5
у
3
2
1
x
-1
-3
-5
у
1
3
5
-2.
-4
-6
y
1-5
1-7
-9
х
--2
-3
-4
у
0
-1
1-2
I

Answers

Answer:

I'd say the second one. the others are all showing a linear relatiknship

Someone please help me

Answers

37.
13 - 7 = 6
Her Mom Uses 6

38.
9 + 8 = 17
Andrew Had 17 Muffins

HELP FAST FAST FAST
IM GIVING BRAINLIEST!!!!

A trapezoid has an area of 13.5 inches. The bases are 3 inches and 6 inches. Determine the height of the trapezoid.

EXPLAIN THE PROCESS AND THE STEPS PLEASEEE

Answers

Answer:

h=3in  

Step-by-step explanation:

A=a+b

2h

Solving forh

h=2A

a+b=2·13.5

3+6=3in

Janet is writing a book. She writes 3 pages every 2 days. If she continues at the same
pace, how long will it take her to write a 400-page book?
Which proportion could be used to solve this problem?

Answers

It will take her 6 days to write a book because 3 times 2 equals 6

HELP ASAP!! In a right triangle, the longer leg is twice the shorter leg and the hypotenuse is 8 more than the shorter leg. Find the length of the shorter leg.

Answers

Answer:

We can't find an exact number, but the answer is x.

plz help right now plz

Answers

125, 150 , 175, 200 , 225 because you just continue to add $25 for each hour

Find cos (P)
Q
74
70
P
24
R
A.
37
12
В.
35
37
C.
12

Answers

Answer:

cos P = 71.09

Step-by-step explanation:

cos = [tex]\frac{adajcent}{hypotenuse}[/tex]

cos P = [tex]\frac{24}{74}[/tex]

cos P = 0.324

cos-1 of 0.324 is 71.09

cos P = 71.09

Need it now. I'll give you another 100 when done if all i right.

Answers

This it the test please do as fast as posible and show work. thank you and sorry

Need answers for 1 and 2. Please

Answers

Answer:soultion

Step-by-step explanation:      solution

Answer this correctly I’ll give brainalist + 10 points

Answers

Answer:

x = 43

Step-by-step explanation:

Since these angles are inside a right angle, we know their sums are complementary (they add up to 90°.)

x + x + 4 = 90

2x + 4 = 90 | Combine x's

2x = 86 | Subtract 4 from both sides

x = 43 | Divide both sides by 2

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