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.
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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The population of a city increases by 3% per year. If this year's population is 298,0 what will next year's population be, to the nearest individual?
Answer:
5 Probability
5.1 Probabilities
Probabilities are used to describe how likely or unlikely it is that something will happen.
Weather forecasters often talk about how likely it is to rain, or perhaps snow, in particular
parts of the country.
Worked Example 1
(a) When you roll a dice, which number are you most likely to get?
(b) If you rolled a dice 600 times how my sixes would you expect to get?
(c) Would you expect to get the same number of ones?
Solution
(a) You are equally likely to get any of the six numbers.
(b) You would expect to get a six in about 1
6
of the throws, so 100 sixes.
(c) Yes, in fact you would expect to get about 100 of each number.
Worked Example 2
Use one of the following to describe each one of the statements (a) to (d).
Certain
Very likely
Likely
Unlikely
Very unlikely
Impossible
(a) It will snow tomorrow.
(b) It will rain tomorrow.
(c) You win a car in a competition tomorrow.
(d) You are late for school tomorrow.
Solution
(a) Very unlikely for most places in Britain, especially in summer.
(b) Likely or Very likely in Britain in winter.
(c) Very unlikely if you have entered the competition. Impossible if you have not
entered the competition.
(d) Very unlikely, unless the school bus breaks down.
what do you understand by resultant of a force
Answer:
When a system of forces is acting on an object, the difference between the forces is called the Resultant force. For example, a 3N force to the left and 10N force to the right gives a resultant force of 7N to the right.
Step-by-step explanation:
Every morning, Jim goes for a morning walk. His normal walking speed is 3 1/2 km per hour, and he walks
a total distance of 10 km every day. How much time does he take to cover one km?
minutes
Answer:
29 1/31 minutes
What is a irregular concave polygon
Answer:
An irregular polygon is any polygon that is not a regular polygon. It can have sides of any length and each interior angle can be any measure. They can be convex or concave, but all concave polygons are irregular since the interior angles cannot all be the same.
Step-by-step explanation:
It cost Ms. Nelson $245 to buy 5 kids tickets to Disney. How much do the tickets cost per child?
Answer:
49$
Step-by-step explanation:
245/5
What is the length of the hypotenuse of the triangle when x = 9?
7x +41
5x
The length of the hypotenuse is about
(Round to the nearest tenth as needed.)
I NEED THIS ASAP
Answer:
[tex]H = 53.30[/tex]
Step-by-step explanation:
Given
[tex]Side\ 1 = 7x + 41[/tex]
[tex]Side\ 2 = 5x[/tex]
Required
Determine side x
The hypotenuse (H) is calculated using:
[tex]H^2 = Side\ 1^2 + Side\ 2^2[/tex]
[tex]H^2 = (7x + 41)^2 + (5x)^2[/tex]
Substitute 9 for x:
[tex]H^2 = (7*9 + 41)^2 + (5*9)^2[/tex]
[tex]H^2 = 10816 + 2025[/tex]
[tex]H^2 = 12841[/tex]
So:
[tex]H = \sqrt {2841[/tex]
[tex]H = 53.30[/tex]
Mr.moss has 4 gallons of paint. He painted 8 doors. How many benches can he paint with the paint that is left
Answer:
2
Step-by-step explanation:
I did 8 divided by 4 which is 2.
I hope this helps.
hello please help 50 points and brainliest!!!
Answer:
sorry the image is not clear
What is the surface area of the square pyramid?
6 square meters
16 square meters
28 square meters
49 square meters
Answer:
It's 16, there's so many question on this one.
Step-by-step explanation:
two packages of rice cost the same amount. Which is the better buy? 12 ounce or 400 grams
Answer:
400 grams
Step-by-step explanation:
12ounce= 340.19 grams approximately
So,its best to buy the package that weighs 400 grams
Which of the following is NOT a requirement of the Combinations Rule, , for items that are all different? Choose the correct answer below. A. That order is taken into account (consider rearrangements of the same items to be different sequences). B. That r of the n items are selected (without replacement). C. That there be n different items available. D. That order is not taken into account (consider rearrangements of the same items to be the same).
Answer: A. That order is taken into account (consider rearrangements of the same items to be different sequences).
Step-by-step explanation:
The combination is usually given by the formula below:
C n,x = n! / x! (n-x)!
We should note that the requirements for a combination rule include:
• That r of the n items are selected (without replacement).
• That there be n different items available.
• That order is not taken into account (consider rearrangements of the same items to be the same).
Therefore, the option that is not a requirement of the Combinations Rule, , for the items that are all different will then be option A"That order is taken into account (consider rearrangements of the same items to be different sequences).
what is dangerous about living for seven days on just one can of sardines?
Answer:
because you cant survive without enough food.
Step-by-step explanation:
How many solutions does the following equation have 6x-4=-4+6x
¿Cuál es el área de la figura de abajo?
10 cm por 4cm
Answer:
40 cm
Step-by-step explanation:
10x4= 40
Answer:
A=h.a+b/2
A=3cm.4cm+10cm/2
A=21cm^2
Es 21
Me puedes dar Brainliest porfavor
Step-by-step explanation:
Find the geometric mean of 6 and 42. In radical form
Answer: 6√7
Step-by-step explanation:
Geometric Mean: Multiply the 2 numbers and take the square root.
6 · 42 = 252
Now take the square root:
√252
Simplify the radical (if needed):
6√7
Your geometric mean is 6√7.
Hope this helps!
Can someone answer this please!!! I only have 5 mins and u will get Brainly too :)
Answer:
18 units square
Step-by-step explanation:
Given
The attached trapezium
Required
Determine the area
From the attachment, the height, h is:
[tex]h = 3\ units[/tex]
And parallel sides are:
[tex]s_1 = 3[/tex]
[tex]s_2 = 9[/tex]
So, the area is calculated as:
[tex]Area = \frac{1}{2}(s_1 + s_2) * h[/tex]
[tex]Area = \frac{1}{2}(3 + 9) * 3[/tex]
[tex]Area = \frac{1}{2} * 12 * 3[/tex]
[tex]Area = \frac{36}{2}[/tex]
[tex]Area = 18[/tex]
can you solve these please and show your work
Jake cuts out five-pointed stars. They are different sizes, but they
all have the same shape. The side lengths within each star are the same.
To find the perimeter of each star, Jake uses the expression
12£ + ½ - 4€ - 8.5 + 2€ + 8, where e is the side length of the star.
Find the perimeter of a star with side length 6 inches. :( pls help me
What is the perimeter of the shape?
40 feet
43 feet
51 feet
67 feet
Answer:
201
Step-by-step explanation:
40+43+51+67=201
Answer:
its 40
Step-by-step explanation:
4. Write a fraction that is a multiple of 4/5
Answer:
multiply by any number to create a multiple
Step-by-step explanation:
4/5 = 8/10 = 12/15 = 16/20...
Please I need help it’s an emergency
Answer:
i think its b
Step-by-step explanation:
i might be wrong but i think its
[tex]4 \sqrt{3 } [/tex]
please help asap !!! In the graph shown above, which line has a slope value less than −2
Answer: Line J
A is the answer
What is a common denominator?
least common denominator is the lowest common multiple of the denominators of a set of fractions. It simplifies adding, subtracting, and comparing fractions.
Answer:
12
Step-by-step explanation:
Because it is the lowest number that both 4 and 6 can reach by multiplying with whole numbers
:)
A boy is flying a kite and has let out 300 feet of string. He notices that the angle the string makes with the ground is 38 degrees. How high over the ground is the kite?
Answer:
height = 184.7 feet
Step-by-step explanation:
sin 38 = height/300
0.6157 = height/300
height = 184.7 feet
3.663 to the nearest tenth of a ounce
Answer:
3.7 ounces
Step-by-step explanation:
You just need to round to nearest 10th place, which is just next number after decimal. Hope it helps ;)
que expresision algebraica es P (x)=3x - 5x +6?
A news report states that the 99% confidence interval for the mean number of daily calories consumed by participants in a medical study is (1850, 2000). Assume the population distribution for daily calories consumed is normally distributed and that the confidence interval was based on a simple random sample of 18 observations. Calculate the sample mean, the margin of error, and the sample standard deviation based on the stated confidence interval and the given sample size. Use the t distribution in any calculations and round non-integer results to 4 decimal places.
Answer:
The sample mean is of 1925 calories.
The margin of error is of 75 calories.
The sample standard deviation is of 109.7992 calories.
Step-by-step explanation:
Sample mean:
The sample mean is the mean value of the two bounds of the confidence interval. So
[tex]M = \frac{1850 + 2000}{2} = 1925[/tex]
The sample mean is of 1925 calories.
The margin of error
Difference between the bounds and the sample mean. So
2000 - 1925 = 1925 - 1850 = 75 calories.
The margin of error is of 75 calories.
Sample standard deviation:
Here, I am going to expand on the t-distribution.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 18 - 1 = 17
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 17 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.99}{2} = 0.995[/tex]. So we have T = 2.898
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}}[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
Since [tex]M = 75, T = 2.898, n = 18[/tex]
[tex]M = T\frac{s}{\sqrt{n}}[/tex]
[tex]75 = 2.898\frac{s}{\sqrt{18}}[/tex]
[tex]s = \frac{75\sqrt{18}}{2.898}[/tex]
[tex]s = 109.7992[/tex]
The sample standard deviation is of 109.7992 calories.
how do you find the area of a rectangle that has a width of 20,length of 25,
Answer:
20 times 25 which is 500.
Step-by-step explanation:
To get the area of a rectangle do length times width, just like a square!
In ΔEFG, e = 4.7 inches, f = 4.8 inches and g=3.6 inches. Find the measure of ∠E to the nearest 10th of a degree.
Answer:66.3
Step-by-step explanation: