The random variable X is the number of siblings of a student selected at random from a particular secondary school. Its probability distribution is given in the table. Find the standard deviation of the random variable. Round to three decimal places. x 0 1 2 3 4 5 P(X= x) 11 7 3 1 1 1 48 24 16 6 12 24

Answers

Answer 1

Answer:

1.41

Step-by-step explanation:

Given the table :

X : _____0 ___ 1 ____ 2 ____ 3 ____ 4 ____5 P(X= x)_ 11/48_7/24_ 3/16____1/6___ 1/12 __1/24

The standard deviation = √var(x)

The Variance : Var(X) = (Σx²*p(x)) - μ²

μ = E(X) = Σ(X * p(x)) :

Σ(X * p(x)) = (0*(11/48))+(1*(7/24))+(2*(3/16))+(3*(1/6))+(4*(1/12))+(5*(1/24))

μ = 1.70833333

Var(X): [(0^2*(11/48))+(1^2*(7/24))+(2^2*(3/16))+(3^2*(1/6))+(4^2*(1/12))+(5^2*(1/24))] - 1.70833333^2

= 4.9166667 - 2.9184027663889

Std (x) = √1.9982639336111

Std (x) = 1.4135996

Std (x) = 1.41

Answer 2

Answer:

The Standard deviation of the random variable is 1.414.

Step-by-step explanation:

We Know,

Standard deviation= [tex]\sqrt{variance}[/tex]

Variance is given by:

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

Given,

[tex]x = 0\ 1\ 2\ 3\ 4\ 5\\P(X=x)= \frac{11}{48} \ \frac{7}{24} \ \frac{3}{16}\ \frac{1}{6}\ \frac{1}{12}\ \frac{1}{24} \\[/tex]

[tex]E(X)=[/tex]∑ [tex]x*P(X)[/tex]

[tex]E(X) = 0+ 1*\frac{7}{24} + 2*\frac{3}{16} + 3*\frac{1}{6} + 4*\frac{1}{12} + 5*\frac{1}{24}\\= 1.7083[/tex]

[tex]E(X^{2} ) =[/tex][tex]0+ 1^{2} *\frac{7}{24} + 2^{2} *\frac{3}{16} + 3^{2} *\frac{1}{6} + 4^{2} *\frac{1}{12} + 5^{2} *\frac{1}{24}[/tex]

[tex]= 4.9167[/tex]

So,

[tex]Var(X)= 4.9167- 1.7083^{2}[/tex]

[tex]= 1.99841\\\\Hence, Standard Deviation= \sqrt{1.99841} \\\\ Standard Deviation= 1.413( (upto 3 decimals)[/tex]

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Related Questions

If the variables cancel on each side, and the given equation is TRUE, for example 3=3, then the equation has NO SOLUTION. TRUE OR FALSE

Answers

Answer: False

Reasoning: An equation that is true has an infinite amount of solutions.

In a particular country railroad miles have been on the decline and the miles of roads in the highway system have been increasing. The function y=-1250.2x + 142,602 represents the railrond miles, while the function y=501.5x + 158,449 models the number of

highway miles. For each function, x is the number of years after 1995


b. Find the year in which it is estimated that the number of the country's railroad miles and the number of the country's highway miles were the same.

It is estimated that the number of railroad miles and the number of highway miles were the same during the year ___.(Round down to the nearest your)

Answers

Answer:

1986

Step-by-step explanation:

Function that represents railroad miles

[tex]y=-1250.2x + 142602[/tex]

Function that represents number of highway miles

[tex]y=501.5x + 158449[/tex]

We have to find in which year (1995+x) the miles of railroad and highway is the same so

[tex]-1250.2x + 142602=501.5x + 158449\\\Rightarrow -1250.2x-501.5x=158449-142606\\\Rightarrow -1751.7x=15843\\\Rightarrow x=-\dfrac{15843}{1751.7}\\\Rightarrow x=-9.044\ \text{years}\approx -9\ \text{years}[/tex]

So, the year is [tex]1995+x=1995+(-9)=1986[/tex]

In the year 1986 the railroad and highway miles were equal.

It is estimated that the number of railroad miles and the number of highway miles were the same during the year 1986.

Given

The function y =-1250.2x + 142,602 represents the railrond miles.

While the function y =501.5x + 158,449 models the number of highway miles.

For each function, x is the number of years after 1995.

The year in which it is estimated that the number of the country's railroad miles and the number of the country's highway miles were the same.

Therefore,

[tex]\rm -1250.2x + 142,602=501.5x + 158,449\\\\-1250.2x -501.5x = 158,449-142,602\\\\-1751.7x=15847\\\\x = \dfrac{15847}{-1751.7}\\\\x=-9[/tex]

Then,

1995 - 9 = 1986

It is estimated that the number of railroad miles and the number of highway miles were the same during the year 1986.

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What is the solution to this equation?
-6x+ 3 = 21
O A. x=-3
O B. x= 3
O C. x=-4
O D. x = 4

Answers

Answer:

A -3

Step-by-step explanation:

-6 times -3 = Postive 18. then 18+3=21

:). Hope that helped

A.x=-3 -6x+3=21 -6x+3-3=21-3

There are 279 middle school students signed up for a field trip. An adult needs to be assigned to guide every 8 students. Mr. Corcoran determines that 34 adults are needed for the field trip. Explain whether or not Mr. Corcoran is correct.

Answers

Answer:

No, because 3 students would be left over and we have to make an extra so 35. Mr.Smith is wrong.

Step-by-step explanation:

system of equations
3x+5y=-7

6x-4y=0​

Answers

Step-by-step explanation:

18x+30y=-7

18x+12y=0

42y=-7

y=-0.17

3x+5(-0.17)=-7

3x-0.85=-7

3x=-6.15

x=-2.05

The entrance for the amusement park is $40, visitors purchase additional $2
tickets for rides, games and food. How many tickets can you buy if you
brought $100 to spend at the park?

Answers

Answer:

2 tickets because round

Step-by-step explanation:

make an equation: 100=40x+2 and solve

2.45 tickets so only two

40+40 =80

100-80=20

but 100-2=98 so there is only 18$ left so not enough for another ticket

Answer:

30 Tickets

Step-by-step explanation:

In the question, it said that $40 is the entrance fee. Then, it said that visitors purchase additional tickets for rides, games, and food. This means that EACH ticket is 2 dollars.

Hence, $40 (entrance fee) + $2 (each ticket price) x (the number of tickets spent) = 100 (total amount of money).

So, the equation should be 40 + 2x = 100, which means x = 30.

100 - 40 = 60

60/2 = 30

30 tickets can be purchased

Which of these numbers is greater than 2.25 but less than 1? Is it 1 or 1.5 or 0 or 2.5....

I think the answer is 1.5 but can someone tell me how I came up with this answer. He has to write it down.

Answers

Answer:

the answer is 1.5 of course because converting them into their fractional form indeed informs u that 1.5 is the solely answer

!!!Plz help!!Choose the most appropriate name for the function described below.
The amount of bread depends on the amount of flour used to make it.
A. Flour(amount), or F(a)
B. Bread(flour), or B(0)
C. Flour(bread), or F(b)
D. Bread(amount), or B(a)

Answers

Answer:

Step-by-step explanation: The answer is Bread(flour) or b(f)

A quadratic equation is written as a system of two quadratic functions. Select the number of possible ways the graphs can intersect.

Answers

Answer:

can I see the opinions and I will come

Step-by-step explanation:

back and edit my question and answer it for you

Answer:

0, 1, 2, infinite

Step-by-step explanation:

The world's largest fruitcake was made by Dr.Fabrizio Sepe of Italy.It was 4,353kg.If each serving size was 200 grams.How many people could the fruitcake serve?

Answers

Answer:

i believe your answer would be 21,765

Step-by-step explanation:

since there are 1000 grams in a kilogram the equation would be 4353÷.200

rosy wants a large picture window put in her living room of her new house. the window is to be square with an area of 49 square feet. how long should each side of the window be

Answers

7

the square root of 49 is 7

The odds that it will snow tomorrow are 9 to 6. What is the probability that it will not snow tomorrow?a) 0.1818
b) 0.2222
c) 0.1111
d) 0.1667
e) 0.8182

Answers

Answer:

a) 0.1818

Step-by-step explanation:

Given that:

The odd that it'll snow tomorrow is 9 to 6

The probability that it will snow tomorrow  [tex]=\dfrac{9}{9+6}[/tex]

[tex]=\dfrac{9}{15}[/tex]

= 0.6

The probability that it'll not snow tomorrow [tex]= 1 - \dfrac{9}{15}[/tex]

[tex]= \dfrac{15-9}{15}[/tex]

[tex]=\dfrac{6}{15}[/tex]

= 0.4

Let assume that the odd that it'll snow tomorrow is 9 to 2

The probability that it will snow tomorrow  [tex]=\dfrac{9}{9+2}[/tex]

[tex]=\dfrac{9}{11}[/tex]

= 0.8181

The probability that it'll not snow tomorrow  [tex]= 1 - \dfrac{9}{11}[/tex]

[tex]= \dfrac{11-9}{11}[/tex]

[tex]=\dfrac{2}{11}[/tex]

= 0.1818

None of the  options is correct.

Probability that it will not snow tomorrow = 0.4

The odds of an event E is defined as formulated in equation (1)

[tex]\rm Odd\; of\; event\; E = P(E)/P(\bar E) = P(E)/(1-P(E)).......(1)[/tex]

Let P(E) represents the probability that it will snow tomorrow.

Let event E represents the event that " it will snow tomorrow "

So the odds of the event that it will snow tomorrow

[tex]\rm \dfrac{P(E)}{P(\bar E)} =\dfrac{9}{6} = \dfrac{P(E)}{1-P(E)}.......(2)[/tex]

On solving equation (2) we get

[tex]\rm P(E) = \dfrac{9}{15}[/tex]

So the probability that it will snow tomorrow is 9/15

Hence the probability that it will not snow tomorrow

[tex]\rm P(\bar E) = 1- \dfrac{9}{15} = \dfrac{6}{15} =\bold{0.4}[/tex]

Probability that it will not snow tomorrow = 0.4

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Help plzz Math honors algebra

Answers

The answer to the problem is N=6

Answer: n = 6. Hopefully this helps!

^ABC is similar to ^EDC shown below.
Which equation could be used to determine x, the
length of CD?

Answers

Answer:

last one 12/8 = 9/X

Step-by-step explanation:

according to the rule of similarity in triangles

The equation that can be used to find the length of CD is 9/x = 12/8.

Where x is CD.

Option D is the correct answer.

What is a triangle?

It is a two-dimensional figure which has three sides and the sum of the three angles is equal to 180 degrees.

We have,

ΔABC ≅ ΔEDC

We can write:

BC/BA = CD/DE

9/12 = x/8

9/x = 12/8

Thus,

The equation 9/x = 12/8 can be used to find x.

Learn more about triangles here:

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#SPJ2

Study the diagram of circle C, where two chords, AB and DE, are equidistant from the center.

If AB=3x − 7, and DE = 5(x − 5), what is the length of AB?
Enter the correct value.

Answers

The answer to what is the length of AB and the correct value is 20

I got a 100% on test

What is the perimeter of the figure?

A. 22.0 yd2
B. 21.1 yd
C. 22.0 yd
D. 21.1 yd2

Answers

Answer:

B. 21.1 yd

Step-by-step explanation:

The perimeter of the figure is the sum of all its three sides.

Take note that the dotted line is not a side length of the figure.

The side lengths are 9 yd, 5 yd, and 7.1 yd.

Therefore, the perimeter of the figure = 9 + 5 + 7.1

Perimeter = 21.1 yd.

Also, take note of the unit of the perimeter. Unit of the perimeter would not be squared. Only area has a unit that is squarred.

Wow, using grammar makes me feel like an adult!

Answers

Answer:

I asked my teacher if we could use that she said it's considered cheating, I still use it

Step-by-step explanation:

Can anyone help with this?

Answers

Answer:

The answer is B and D.

Step-by-step explanation:

I hope this helped and if it did I would appreciate it if you marked me brainliest. Thank you and have a nice day!

Frank wants to go bowling. The bowling alley charges $4 per game and a one-time charger of $3 for bowling shoes. Look at the information below:



y = 4x + 3

y is the total cost of bowling

x is the number of games bowled



Based on the information, which statement is true?

Answers

Report that other guy smh... but im not quite too sure but i believe the answer you were looking for was C. The total cost will increase by 4$ every 3 games bowled :D

8 more than the quotient of a number and 2 is 14. find the number

Answers

Answer:

x = 12

Step-by-step explanation:

x/2 + 8 = 14Subtract 8 from both sides because it is the inverse operation of addition. x/2 = 6Multiply both sides by 12 because it is the inverse operation of division. x = 12

PLEASE HURRY!!! I ONLY HAVE FIFTEEN MINUTES TO ANSWER.


Which polynomial correctly combines the like terms and expresses the given polynomial in standard form?

8mn5 – 2m6 + 5m2n4 – m3n3 + n6 – 4m6 + 9m2n4 – mn5 – 4m3n3


a. n6 + 7mn5 + 14m2n4 – 5m3n3 – 6m6

b. –2m6 – 5m3n3 + 14m2n4 + 7mn5 + n6

c. 14m2n4 + 7mn5 – 6m6 – 5m3n3 + n6

d. n6 – 6m6 + 7mn5 + 14m2n4 – 5m3n3

Answers

Answer c is the correct option:) the explanation is complicated just like the question lol

Answer:

c

Step-by-step explanation:

What’s the numerator for the following rational expression please I need help quick taking test currently

Answers

Answer:

Well, the most reasonable explanation would be j+8 or 8+j

1
After becoming completely blind at the age of
sixty-four, what did Leonhard Euler do?

Answers

Answer:

his remarkable mathematical flow continued without interruption – in fact, it increased.

Step-by-step explanation:

what is principal in simple intrest​

Answers

You have to pay extra money when you pay it back after you borrow it.So interest is: the amount of money you pay back on top of the original money you borrowed. The meaning of the word principal is: the original amount of money you borrowed.

What is the domain of y = sqrt(x + 7) + 5 ?

Answers

Answer:

Step-by-step explanation:

İnside the root cannot be negative so x+7 at least equal to 0 so x is at least-7 so the answer is bigger or equal to -7

Answer:

the actual answer is y>=5 or b

Step-by-step explanation:

edge 2020

The recently released iPhone XS Max comes in three different storage sizes: 64GB, 256GB, and 512GB. The price of the 64GB phone is $1,099. If prices were proportional to the phone's storage size, how much would the 256GB phone and the 512GB phone cost

Answers

very much alot of very large amouts of big moneys that are worth a large amout

the ratio of the number of adults to the number of children in a library is 12:5 if there are 45 children in the library how my adults are there at the library.

Answers

I’m guessing 108. 45 divided by 5 is 9, so 9 times 12 is 108.
There will be 108 adults.
Since the number of children are 45 and the ratio of adults to children is 12:5, divide 45/5. That equals 9.
So since you have that down, multiply 12x9. That equals 108.

if receiver travels 54 yards in 9 seconds whats the average speed

Answers

Answer:

Step-by-step explanation:

The average speed is 6 yards in 1 second!

GO CHEIFS!

Hope it helps

Answer:

6

Step-by-step explanation:

To find the average speed which is also the unit rate you simply need to divide the two numbers.

54 ÷ 9 = 6

So, 6 yards is your average speed.

Make me brainliest

A 3x33 cube is built out of twenty-seven 1x1x1 blocks. Then,
seven ixi blocks are removed. Specifically, the center block
from each of the six faces of the cube is removed and the center
block of the cube is removed. What is the total surface area of
the modified cube?

Answers

Answer:-7^2(negitive seven to the second power)

Step-by-step explanation:

son
Undaunted co
American re
Draw a line representing the "rise" and a line representing the "run" of the line. State
the slope of the line in simplest form?

Answers

Answer:

Slope = [tex]\frac{1}{2}[/tex]

Step-by-step explanation:

Let's take two points on the line graphed for a function.

Slope of this linear function = [tex]\frac{\text{Rise}}{\text{Run}}[/tex]

Between two points chosen,

Rise = Vertical distance on y-axis (Increase or decrease) from one point to the second

Run = Horizontal distance on x-axis from one point to second

Let the points on the graph are (-8, 0) and (0, 4).

Rise = 4

Run = 8

Therefore, slope of the line = [tex]\frac{\text{Rise}}{\text{Run}}[/tex] = [tex]\frac{4}{8}[/tex]

Slope = [tex]\frac{1}{2}[/tex]

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