Suppose that the test score of a student taking the final of a probability course is a random variable with mean 76.

Required:
a. Give an upper bound for the probability that a student's test score will exceed 86. Suppose, in addition, that the professor knows that the variance of a student’s test score is equal to 25.
(b) What can be said about the probability that a student will score between 65 and 85?
c. How many students would have to take the examination to ensure, with probability at least .9, that the class average would be within 5 of 75? Do not use the central limit theorem.

Answers

Answer 1

Answer:

a. 0.8837

b. 0.6914

c. 10 student

Step-by-step explanation:

a. using markov's inequality; P(u >= X)<= E(u) / X

   mean u = 76

   X, test score = 86

= 76 / 86 = 0.8837

b. variance v = 25

   The test is between 65 and 85 P(65 <= X <= 85);

   P(|65 - X|<= |X - u| <= |85 - X|) = P(65 - 76 <= |X - u| <= 85 -76)

   = P(-11 <= |X - u| <= 9)

   = P(|X - u| <= 9)

using the chebyshev's inequality;

P(|X - u| <= 9) = 1 - variance / (standard deviation of individual test score)^2

   = 1 - 25/ 9^2

   = 1 - 25/81 = 1 - 0.3086 = 0.6914

c. P(|X - 76| <= 5) = 0.9

still using chebyshev's inequality;

= 1 - variance / lower limit^2 (E)

where E = 1 - 0.9 = 0.1

lower limit = 5

= 1 - 25/ 5^2 (0.1) = 10


Related Questions

A line includes the points (-8,8) and (6,4). Select the correct point slope form equations of this line. (Remember there can be more than one)



Group of answer choices

y-8=(-2/7)(x+8)

y+8=(-2/7)(x-8)

y-4=(-2/7)(x-6)

Answers

Answer:

y-8=(-2/7)(x+8) and y-4=(-2/7)(x-6)

Step-by-step explanation:

Point slope form equation: y - y₁ = m(x - x₁)

m is the same for all your answer choices, so you can disregard that part.

First point: (-8,8)

x₁ = -8; y₁ = 8

Plug those values into the point slope form equation and you get:

y-8=(-2/7)(x+8)

Do the same for the second point, and you get:

y-4=(-2/7)(x-6)

Answer:

first and third options

Step-by-step explanation:

The equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

Calculate m using the slope- formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (- 8, 8) and (x₂, y₂ ) = (6, 4)

m = [tex]\frac{4-8}{6+8}[/tex] = [tex]\frac{-4}{14}[/tex] = - [tex]\frac{2}{7}[/tex]

using (a, b ) = (- 8, 8 ), then

y - 8 = - [tex]\frac{2}{7}[/tex] (x - (- 8) ) , that is

y - 8 = - [tex]\frac{2}{7}[/tex](x + 8) ← first option

using (a, b ) = (6, 4 ), then

y - 4 = - [tex]\frac{2}{7}[/tex] (x - 6) ← third option

A large pot of water is heating up on a stove at a constant rate. After three minutes of heating it had a temperature of 100 ℉. After nine minutes of heating the temperature was at 148 ℉. Let T be the temperature and n be the number of minutes. Write a linear equation for T in terms of n.

Answers

Answer:

Given function:

y=9.5x+62.1

We have to find the number of minutes x, when y=138.1°F

Put value of y in function.

138.1=9.5x+62.1

Subtract 62.1 from both sides.

76=9.5x

Divide both sides by 9.5.

8=x

or

x=8 minutes

Answer: After 8 minutes the temperature of water will be 138.1°

Step-by-step explanation:

Answer:

T= 8n+76

Step-by-step explanation:

First you need to find the average rate of change:

( 3, 100)

(9,148)

Subtract:

148-100= 48

9-3= 6

Then divide them:

48/6=8

This is your slope, now we must find our y- intercept by using the formula

y= mx+b:

y=mx+b

Plug in what you know:

y= 8x+b

To find your y-intercept use one of the 2 points above, either (3,100) or (9,148)

Plug in your x's and y's into your almost complete equation:

100= 8(3)+b

Then solve to get b:

You should get b=76

Hope this helps

What is the answer I need help pls

Answers

Answer:

The answers are,

-3, -7

-2, 4

0, 2

2, 8

3, 11

Step-by-step explanation:

You just plug in the domain values into the equation and solve for f(x), so your domain number is your x value and the y value(f(x) value) is the answer

There are 32 desks in a room,
If x represents the number of rows of desks, which expression would equal the number of desks in each row?
32 x
32-x.
32 +x
32/x

Answers

Answer
32/x
Explanation
I think this is correct, the others wouldn’t make sense

The expression would equal the number of desks in each row is 32/x. Therefore, option D is the correct answer.

Given that, there are 32 desks in a room.

What is an expression?

An expression is a combination of terms that are combined by using mathematical operations such as subtraction, addition, multiplication, and division.

Now, x represents the number of rows of desks.

The number of desks in each row = Total number of desks in a room / The number of rows of desks

= 32/x

The expression would equal the number of desks in each row is 32/x. Therefore, option D is the correct answer.

To learn more about an expression visit:

https://brainly.com/question/13947055.

#SPJ5

What does the arrow represent?
Bouncing a Ball Height ha 0 Time

a. the ball is hitting the ground for the first time
b. the ball has hit the ground for the third time and is rising
c. the ball has reaches the maximum height of the first bounce
d. the ball has been thrown and is traveling towards the ground ​

Answers

Answer:

b number is the correct answer of the question

Answer:its a

a

Step-by-step explanation:

These points are linear. Find the slope.

Answers

Answer:

5

Step-by-step explanation:

To find the slope of a line, you need to find the [tex]\frac{rise}{run}[/tex] between two points. I will be calculating the slope using the two points (2, 10) and (3, 15).

Slope = [tex]\frac{rise}{run}[/tex]

          = [tex]\frac{15-10}{3-2}[/tex]

          = 5

what is m% of n please help

Answers

m% of n would technically be some amount of n. To find m%, you would have to do n * 0.m to find your answer

If the store paid $75 for a clarinet and sold it for $100, did the store mark up the price by 30%?

Answers

Answer:

No

Step-by-step explanation:

30% of $75 is $22.50 (0.3×75=22.5)

$75+$22.50=$97.50, not $100

So, the store did not mark up the price by 30% because the original price ($75) plus 30% more does not equal $100.

Answer:

no

Step-by-step explanation:

The length of a rectangle is 4 more than twice the width length. The perimeter is 28. What is the LENGTH?

Answers

Answer:

10[tex]\frac{2}{3}[/tex]

Step-by-step explanation:

Let the width length be x.

Width length = x

Length = 2x + 4

Perimeter = width + length + width + length

                = x + 2x + 4 + x + 2x + 4

                = 6x + 8

6x + 8 = 28

6x = 28 - 8

    = 20

x = 20 ÷ 6

x = 3[tex]\frac{1}{3}[/tex]

Length (2x + 4) = 2(3[tex]\frac{1}{3}[/tex]) + 4

                         = 6[tex]\frac{2}{3}[/tex] + 4

                         = 10[tex]\frac{2}{3}[/tex]

Factor using grouping: x³+ 3x² + 5x = 15

Answers

X= 1.288 or just 1.29 is the correct answer. When you factor, set each factor equal to zero.
1. Move all terms to one side of the equation, usually the left, using addition or subtraction.
2. Factor the equation completely.
3. Set each factor equal to zero, and solve.
4. List each solution from Step 3 as a solution to the original equation.

I GIVE BRANLILSET

Maddie prepared 24 kilograms of dough after working 6 hours. How many hours did Maddie work if she prepared 40 kilograms of dough? Assume the relationship is directly proportional.

Answers

Answer:

10 hours

Step-by-step explanation:

24kg dough/6 hours = 4kg dough/hour

4kg dough / 1 hour

*10                *10        (multiply both sides by 10)

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

40kg dough/10hrs

PLS ITS A TEST ILL GIVE BRAINLIEST the equation is y = -3x + 2
y=x-6

Answers

The graph is the second one, when they both meet at (2,-4).

Which of the following slopes of a line passes through points (2, 3) and (4,7) ?
5
2
3
O

Answers

Answer:

2

Step-by-step explanation:

slope = (difference in y)/(difference in x)

slope = (7 - 3)/(4 - 2)

slope = 4/2 = 2

Answer: 2

In a class of 12 boys and 8 girls, two students need to be chosen for classroom jobs.
What is the probability that Mary gets selected?

Answers

Answer:

55 percent chance or 11/20 or  0.55

Step-by-step explanation

I need this done quick pls.

Answers

Answer:

58º

Step-by-step explanation:

The sum of a triangle's interior angles is 180º. We know two interior angles, and we can solve from there: 180-(65+57)=180-65-57=180-180-122=58.

The cost, including sales tax, of a Ford Focus SE is $19,392.70. If the sales tax is 6%, find the cost of the car before the tax was added.

Answers

Answer:

the price before taxes was $18,229.13

Step-by-step explanation:

given that 16 ounces equal 1 pound , how many ounces are in 6.7 pounds

Answers

Answer:107.2

Step-by-step explanation:

Answer:

107.2

Step-by-step explanation:

6 x 16 = 96

.7 x 16 = 11.2

add them to get 107.2

James borrows $4,200 to pay his college tuition. He signs a 5-year simple interest loan. If the monthly payments are $78.40, what is the interest rate on the loan?

Answers

Answer:

2.4%

Step-by-step explanation:

Total amount of payments:

5 years * 12 months/year * $78.40/month =

= $4704.00

Amount of interest paid in 5 years:

$4704 - $4200 = $504

Amount of interest paid in 1 year:

$504/5 = $100.80

Annual percent rate of interest:

$100.80/$4200 * 100% = 2.4%

Answer: 2.4%

5/12<__<3/4 what answer goes in the blank

Answers

Answer:

We have:

5/12<__<3/4

To complete the blank, we need to find a number that is larger than 5/12, but smaller than 3/4.

This is ratter easy, the first step would be to write both limits with the same denominator.

we can rewrite the upper one as:

3/4 = (3/3)*(3/4) = 9/12

Where we multiplied the numerator and denominator by the same number, 3.

Now we have:

5/12 <  < 9/12

Then in the blank, we could input any number like:

5/12 + 1/12 = 6/12

6/12 is larger than 5/12, but smaller than 9/12

We also could use 7/12, or 8/12.

And those are the ones easy to find, actually, there are infinite numbers that can fill the blank.

Then to complete the answer we will write:

5/12 > 6/12 > 9/12

possible number of extrema a 4th degree polynomial could have is:

A. 3 or 1 extrema
B. 4 or 2 extrema
C. 5 extrema
D. none ​

Answers

Answer:

A

Step-by-step explanation:

Luis wants to buy Jordans for 75.23. He saves 10.27 per month. Write an equation to solve how many months he'll need to save.

Answers

Answer:

75.23=10.27x

Step-by-step explanation:

x will represent how many months Luis will save and it will equal 75.23. To find the value of x, divide 10.27 on both sides and get x=7.32. That means Luis will need to earn 10.27 for 7.32 months to get Jordans.

If the interest of sum of money is 6 yrs in 3/8 of the principal . what is the rate of interest?​

Answers

Answer :

R = 6.25%

Solution,

Let P is the principal. It means interest will be :

I=3/8 P

The formula for the interest is given by :

[tex]I=\dfrac{PRT}{100}\\\\\dfrac{3}{8}P=\dfrac{PR\times 6}{100}\\\\\dfrac{3}{8}=\dfrac{6R}{100}\\\\R=\dfrac{300}{8\times 6}\\\\=6.25\%[/tex]

Hence, the rate of interest is 6.25%.

which number line correctly graphs the numbers in the list?​

Answers

Answer:

the first option

Step-by-step explanation:

A decking company estimates how many gallons of stain each deck requires before starting construction. Apart from knowing the total area of each deck, which additional quantity will allow the decking company to make an accurate estimation

Answers

Answer:

Concept: Engineering Statistics

To make accurate estimations they need the total volume of the area.Hence they need the area coverage by the selected stain.Solution: Are covered by each gallon of stain This provides an accurate representation to a significant figure.

What basic fact can you use to divide 2,800 by 7

Answers

Step-by-step explanation:

2800/7 = 400, ,

please you can see the upper paper which

can to solve this division math

Nick earns 3.5%
commission on every
car he sells. How much
would he earn if he sold
a $14.000 car?

Answers

The amount he would earn is $490.

What does multiplication mean?

Multiplication is the process of determining the product of a number. It is determined by following some mathematical processes. The sign used to represent multiplication is ×.

How much will he earn?

Commission = 3.5% x $14,000

0.035 x $14,000 = $490

To learn more about multiplication, please check: https://brainly.com/question/13814687

Solve this simultaneous e
x + y = 26
3x + y = 56

Answers

Answer:

x= 15 and y= 11

Step-by-step explanation:

The goal here is to solve

x + y =26 and

3x + y =56 for the variables x and y.

First, let's work on your first equation, x + y =26

After this initial survey of the equations, the system of equations we'll set out to solve is:

x+y = 26 and 3x+y = 56

Let's start by solving x+y = 26 for the variable x.

Move the y to the right hand side by subtracting y from both sides, like this:

From the left hand side:

y - y = 0

The answer is x

From the right hand side:

The answer is 26-y

Now, the equation reads:

x = 26-y

To isolate the x, we have to divide both sides of the equation by the other variables

around the x on the left side of the equation.

and this is the final solution to your equation.

Next, let's solve 3x+y = 56 for the variable y.

Move the 3x to the right hand side by subtracting 3x from both sides, like this:

From the left hand side:

3x - 3x = 0

The answer is y

From the right hand side:

The answer is 56-3x

Now, the equation reads:

y = 56-3x

To isolate the y, we have to divide both sides of the equation by the other variables

around the y on the left side of the equation.

and this is the final solution to your equation.

Now, plug the earlier result, x=26-y, in for x everywhere it occurs in

y=56-3x.

This gives y=56-3(26-y). Now all we have to do is solve this for y,to have our first solution.

26-y evaluates to 26-y

Multiply 3 by 26-y

we multiply 3 by each term in 26-y term by term.

This is the distributive property of multiplication.

Multiply 3 and 26

1

3 × 26 = 78

Multiply 3 and -y

Multiply 1 and y

The y just gets copied along.

y

3 × -y = -3y

3*(26-y) evaluates to 78-3y

56 - 78 = -22

The answer is -22+3y

56-3*(26-y) evaluates to -22+3y

Move the 3y to the left hand side by subtracting 3y from both sides, like this:

From the left hand side:

y - 3y = -2y

The answer is -2y

From the right hand side:

3y - 3y = 0

The answer is -22

Now, the equation reads:

-2y = -22

To isolate the y, we have to divide both sides of the equation by the other variables

around the y on the left side of the equation.

The last step is to divide both sides of the equation by -2 like this:

To divide y by 1

The y just gets copied along in the numerator.

The answer is y

-2y ÷ -2 = y

-22 ÷ -2 = 11

The solution to your equation is:

y = 11

Lastly, to find the solution for x, we plug this answer for y into the earlier result that

x=26-y.

This gives x=26-(11). Now, simplify this.

26-(11) evaluates to 15

x= 15

So, the solutions to your equations are:

x= 15 and y= 11

Answer:

(15, 11 )

Step-by-step explanation:

Given the 2 equations

x + y = 26 → (1)

3x + y = 56 → (2)

Subtract (1) from (2) term by term to eliminate y, that is

2x = 30 ( divide both sides by 2 )

x = 15

Substitute x = 15 into either of the 2 equations and solve for y

Substituting into (1)

15 + y = 26 ( subtract 15 from both sides )

y = 11

solution is (15, 11 )

A boat traveled 54 km with the stream and 42 km against the stream spending a total of as much time as it would spend while travelling 96 km in a lake. Find the speed of boat while it is travelling in the lake, if the current of the river is 3 km/hour.

Answers

Answer:

18 miles / hour

Use the following function rule to find f(-7).
f(x) = 9x - 7
O 70
O-56
0 -70
56

Answers

The correct answer is -70 if you substitute in -7 for c the equation will be = -63 -7 = -70

Answer this question correctly and I will give you brainlyist, 5.0 rating, and thanks. The question that you need to answer is in the screenshots below.

Answers

Answer:

so it should be D because after you check them all D is the only one that the watch would actually cost $50- sorry for the confusing ecplanation but im like 99.99999% sure its right

Step-by-step explanation:

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