Scores on a statistics final in a large class were normally distributed with a mean of 79 and a standard deviation of 12. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least two decimals. (a) Find the 36th percentile of the scores. (b) Find the 70th percentile of the scores. (c) The instructor wants to give an A to the students whose scores were in the top 12% of the class. What is the minimum score needed to get an A

Answers

Answer 1

Answer:

a) The 36th percentile of the scores is of 74.68.

b) The 70th percentile of scores is 85.3.

c) The minimum score needed to get an A is 93.1.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Mean of 79 and a standard deviation of 12.

This means that [tex]\mu = 79, \sigma = 12[/tex]

(a) Find the 36th percentile of the scores.

This is X when Z has a pvalue of 0.36. So X when Z = -0.36.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]-0.36 = \frac{X - 79}{12}[/tex]

[tex]X - 79 = -0.36*12[/tex]

[tex]X = 74.68[/tex]

The 36th percentile of the scores is of 74.68.

(b) Find the 70th percentile of the scores.

This is X when Z has a pvalue of 0.7, so X when Z = 0.525.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]0.525 = \frac{X - 79}{12}[/tex]

[tex]X - 79 = 0.525*12[/tex]

[tex]X = 85.3[/tex]

The 70th percentile of scores is 85.3.

(c) The instructor wants to give an A to the students whose scores were in the top 12% of the class. What is the minimum score needed to get an A?

The 100 - 12 = 88th percentile, which is X when Z has a pvalue of 0.88, so X when Z = 1.175.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]1.175 = \frac{X - 79}{12}[/tex]

[tex]X - 79 = 1.175*12[/tex]

[tex]X = 93.1[/tex]

The minimum score needed to get an A is 93.1.


Related Questions

a number n increased by 18​

Answers

Answer:

n+18

Step-by-step explanation:

Answer: n+18

Step-by-step explanation:

CONCEPT:

- a increased by b=a+b

- a decreased by b= a-b

- a multiply by b=ab

- a divided by b=a/b

SOLVE:

A number n increased by 18

(n) increased by (18)

n+18

Hope this helps!! :)

Please let me know if you have any questions

Any help would be appreciated

Answers

Answer:

$8.25

Step-by-step explanation:

I don't know how to explain it to you but if I'm wrong tell me I'll try it aagain.

A plane traveling 480 miles in 1 hour travels how far in 15 minutes

Answers

Answer:

120 Miles

Step-by-step explanation:

I don’t know how to do this at all

Answers

9514 1404 393

Answer:

  A) down

  B) 25 m; 200 m/s

  C) (20.41, 2065.82)

Step-by-step explanation:

When you are first introduced to equations for ballistic motion, you may be told that the formula is ...

  h(t) = -4.9t² +v₀t +h₀ . . . . . height in meters at time t seconds

where v₀ is the initial upward velocity in meters per second, and h₀ is the initial height in meters.

When you are first introduced to quadratic equations, and the vertex form in particular, you may be told that the form is ...

  f(x) = a(x -h)² +k . . . . . . . vertex (h, k) and vertical scale factor 'a'

When the scale factor (or leading coefficient) is negative the graph of the parabola opens downward. When it is positive, the graph opens upward.

Knowing these things, you are prepared to match the given equation to these patterns.

__

Part A: We observe that the leading coefficient of the function (-4.9) is negative, so the parabola opens down.

__

Part B: The constant in the first given equation is 25, so the initial height is 25 meters.

The coefficient of t in the first given equation is 200, so the initial velocity of the rocket is 200 m/s.

__

Part C: The vertex can be read from the second equation as ...

  (h, k) = (20.41, 2065.82)

Help me ASAP please!!!

Answers

Answer:

7

Step-by-step explanation:

The two angles + 90 degrees equals 180 degrees

So it is sufficient to say that the two angles equals 90 degrees

6r - 7 + 55 = 90

6r + 48 = 90

6r = 42

r = 7

7.

Hope this helps :)!

6C + 47M=893.50
25C + 22M=527.86

Answers

Answer:

C = 4.94   M = 18.38

Step-by-step explanation:

the easiest way is to graph both equaitons and see where they intersect,

see the image

or solve by substitution

6C + 47M=893.50           C = (893.50 - 47M)/6

25C + 22M=527.86

25((893.50 - 47M)/6)  + 22M = 527.86

25/6 [(893.50) - 47M] + 22M = 527.86

25/6 [ - 47M] + 22M = 527.86 - 25/6 [(893.50)

22M - 25(47M)/6  = -3195.06

22M - 195.83M  = -3195.06

      -173.83M   =   -3195.06

                 M  =  18.38

C = (893.50 - 47(18.38)/6

C = 4.94

Find a formula for the exponential function passing through the points
4
3,
and (1,20)
125
f(x) -

Answers

Answer:

[tex]y = 4*5^x[/tex]

Step-by-step explanation:

Given

[tex](x_1,y_1) = (-3,\frac{4}{125})[/tex]

[tex](x_2,y_2) = (1,20)[/tex]

Required

Determine the exponential equation

An exponential equation is of the form: [tex]y = ab^x[/tex]

In: [tex](x_2,y_2) = (1,20)[/tex]

[tex]20 = ab^1[/tex]

[tex]20 = ab[/tex] ---- (1)

In: [tex](x_1,y_1) = (-3,\frac{4}{125})[/tex]

[tex]\frac{4}{125} = ab^{-3}[/tex] --- (2)

Divide (1) by (2)

[tex]20/\frac{4}{125} = \frac{ab}{ab^{-3}}[/tex]

[tex]20/\frac{4}{125} = b^4[/tex]

[tex]20*\frac{125}{4} = b^4[/tex]

[tex]5*125 = b^4[/tex]

[tex]625 = b^4[/tex]

Take 4th roots of both sides

[tex]\sqrt[4]{625} = b[/tex]

[tex]5 = b[/tex]

[tex]b = 5[/tex]

Substitute [tex]b = 5[/tex] in [tex]20 = ab[/tex]

[tex]20 = a * 5[/tex]

Solve for a

[tex]a = 20/5[/tex]

[tex]a = 4[/tex]

Hence, the equation is:

[tex]y = 4*5^x[/tex]

Enter the value of (0.45) divided by 9/10

Answers

The value is .5 or 1/2

There are 20 question in a test and you get 75% correct how many questions do you get right

Answers

Answer:

Answer. so the answer is 15. you got 15 questions right.

Step-by-step explanation:

I think it is 15:) because 5 is 25%, 10 is 50%, 15 is 75% and 20 out of 20 is 100%

The Thompson family is buying a car that can travel 70 miles

Answers

Answer:

The car gets 35 miles per gallons.

Step-by-step explanation:

A farmer is building a fence to enclose a rectangular area against an existing wall. Three of the sides will require fencing and the fourth side is a wall that already exists. If the farmer has 148 feet of fencing, what is the largest area the farmer can enclose?

Answers

Answer:

Step-by-step explanation:

There are several things we need to know to solve this: the perimeter formula of a rectangle, the area formula of a rectangle, and how to complete the square to find the answer. First of all, if the farmer has 148 feet of fencing to enclose 3 sides of a rectangle, the perimeter formula we need will include only 3 sides, the 2 widths and the 1 length:

P = 2w + l; solving for l and filling in our length of fencing gives us:

l = 148 - 2w

The area then for this will be:

A = (148 - 2w)(w) which is the same thing as length times width (area for a rectangle). Multiplying that out gives us:

[tex]A=148w-2w^2[/tex]. Let's rearrange that and put it into descending order so we can complete the square on it:

[tex]A=-2w^2+148w[/tex]

The reason we want to complete the square is because the answer that results from that will give us the dimensions of the rectangle (the width and the length) and also the area. Completing the square maximizes (or minimizes) area.

To complete the square, first factor out the -2 since the leading coefficient when you complete the square has to be a +1. When we do that we get:

[tex]A=-2(w^2-74w)[/tex]. Set it equal to 0 so we can factor it:

[tex]-2(w^2-74w)=0[/tex]

The idea now is to take half the linear term (the term stuck to the w), divide it in half, then square that number. Our linear term is 74. Half of 74 is 37, and 37 squared is 1369. So we add 1369 to both sides, the left side first:

[tex]-2(w^2-74w+1369)=...[/tex]

But we didn't just add in 1369. There's a -2 out front there that refuses to be ignored. It's a multiplier. What we ACTUALLY added in was -2 times 1369 which is -2738; therefore:

[tex]-2(w^w-74w+1369)=-2738[/tex]

The left side can be simplified down to a perfect square binomial:

[tex]-2(w-37)^2=-2738[/tex]

Now we'll add over the -2738:

[tex]-2(w-37)^2+2738=y[/tex] and from there determine our answer. The (w-37) term is the width of the rectangle; therefore, the length is 148 - 2(37) which is 74; the total area if the 2738. Completing the square gives us the vertex form of the parabola; the vertex is (37, 2738) where 37 is the width of the rectangle and 2738 is the max area.

Value of x in this? Having trouble with this problem.

Answers

Answer:

I think it’s 105

Step by step explanation:

I hope this helped in some kind of way.

a seventh grade special education classroom consists of 14 girls and 16 boys. If 10 of the students are selected at random to help a fourth grade math class, determine the probability that all boys will be selected.

Answers

Answer:

8/30015 or .037%

Step-by-step explanation:

16/30 × 15/29 × 14/28 × 13/27 × 12/26 x 11/25 x 10/24 × 9/23 × 8/22 × 7/21

= 8/30015

What is the total surface area of a rectangular prism whose net is shown 19 in. 17in. 6.in.

Answers

Answer:

1078in

Step-by-step explanation:

Surface area =2(wl+hl+hw)

2·(17·19+6·19+6·17)=1078in

Factor 7/10 out of 7/10z+21.

7/10z+21=

Answers

Answer:

1/100 (1471 z + 2100)

0.01 (1471 z + 2100) the result I got

and the Factorization over the splitting field:

14.71 z + 21

What is the value of x?
Enter your answer in the box.

Answers

Answer:

We say that a function is increasing on an interval if the function values increase as the input values increase ...

Step-by-step explanation:

I'm trying to get this question but all i'm getting is links plz somebody answer my question i'm going to fail my I NEEED AN ANSWERRR
Use the table for 12–17.


In the table above, Mr. Maramonte

recorded the score each student in his

class earned on a recent math test.

12. What is the mean score for the students

in Mr. Maramonte’s class?

_______________________________________

13. What is the mean absolute deviation for

the scores to the nearest hundredth?

_______________________________________

14. What is the median score for the

students in Mr. Maramonte’s class?

_______________________________________

15. What is the mode of the data?

_______________________________________

16. Draw a box-and-whisker plot to display

the data.


17. What is the interquartile

Answers

I don’t know I’m so sorry but how are you today?

Amy sells muffins for 1.35 each the muffins cost 0.39 each to make how much profit will Amy make if she sells 48 muffins?

Answers

Answer:

$46.08

Step-by-step explanation:

Hi,

She gets 48 (1.35) when she sells 48 muffins. That equals 64.8.

But she pays 48 (.39) to make them. That equals 18.72.

64.8 - 18.72 = 46.08

She makes $46.08

I hope this helps :)

To solve the equation 5sin(2x)=3cosx, you should rewrite it as___.​

Answers

Answer:

A

Step-by-step explanation:

We want to solve the equation:

[tex]5\sin(2x)=3\cos(x)[/tex]

To do so, we can rewrite the equation.

Recall the double-angle identity for sine:

[tex]\sin(2x)=2\sin(x)\cos(x)[/tex]

By substitution:

[tex]5\left(2\sin(x)\cos(x)\right)=3\cos(x)[/tex]

Distribute:

[tex]10\sin(x)\cos(x)=3\cos(x)[/tex]

We can subtract 3cos(x) from both sides:

[tex]10\sin(x)\cos(x)-3\cos(x)=0[/tex]

And factor:

[tex]\cos(x)\left(10\sin(x)-3\right)=0[/tex]

Hence, our answer is A.

*It is important to note that we should not divide both sides by cos(x) to acquire 10sin(x) = 3. This is because we need to find the values of x, and one or more may result in cos(x) = 0 and we cannot divide by 0. Hence, we should subtract and then factor.

Answer:

A. cosx(10sinx-3)=0

Step-by-step explanation:

5(2sinxcosx)=3cosx

10sinxcosx-3cosx=0

cosx(10sinx-3)=0

Evaluate the expression 2y + 10 + y2 of y=8

Answers

The evaluation of the expression 2y + 10 + y² at y = 8 returns 90 as its value.

How to evaluate a given mathematical expression with variables if values of the variables are known?

You can simply replace those variables with the value you know of them and then operate on those values to get a final value. This is the result of that expression at those values of the considered variables.

The considered expression is 2y + 10 + y²

We need to evaluate it at y = 8

Putting 8 in place of y in the expression, we get:

[tex]2y + 10 + y^2|_{y=8} = 2 \times 8 + 10 + (8)^2 = 16 + 10 + 64 = 90[/tex]

Note that small subscript of y = 8 shows that we're evaluating the expression for y = 8.

Also, when symbols are used with multiplication, we usually hide the multiplication sign and just keep the multiplying quantities close to each other, this is why [tex]2 \times y[/tex] was written 2y in the expression.

Thus, the evaluation of the expression 2y + 10 + y² at y = 8 returns 90 as its value.

Learn more about evaluating a function at a value  here: https://brainly.com/question/2753269

On an international exam; students are asked to respond to a variety of background questions. For the 41 nations that participated in the exam; the correlation between the percentage of items answered in the background questionnaire (used as a proxy for student task persistence) and mean score on the exam was 0.883. Does this suggest there is a linear relation between student task persistence and achievement score

Answers

Answer:

since r > 0.361

we reject H₀

Therefore, Yes, It does suggest that  there is a linear relation between student task persistence and achievement score, since r  [0.883 ] is greater than critical value for 30 [ 0.361 ]

Step-by-step explanation:

Given the data in the question;

n = 41

r = 0.883

H₀ : population correlation coefficient = 0 ( both are independent )

Hₐ : population correlation coefficient ≠ 0 ( there is a linear relation between student task persistence and achievement score )

critical value for n = 30 is 0.361

that means, for n = 41, critical value will be less than 362

now, since r > 0.361

we reject H₀

Therefore, Yes, It does suggest that  there is a linear relation between student task persistence and achievement score, since r  [0.883 ] is greater than critical value for 30 [ 0.361 ]

Is 3(b+c) equivalent expressions?

A. True

B. False

Answers

Answer:

Is 3(b+c) equivalent expressions?

A. True

Answer is: A
Hope this helps :)
Brainliest plzz

What is the resistance of a coil which draws a current of 200na​

Answers

Answer:

600000Ω

Step-by-step explanation:

1μA = 10⁻⁶ A

200μA = 0.0002 A

Potential difference = V = 120 V

Current = I = 0.0002 A

Resistance = R

R = V / I

  = 120 / 0.0002

  = 600000Ω

A random sample of 8 cigarettes of a certain brand has an average nicotine content of 4.2 milligrams and a standard deviation of 1.4 milligrams. Is this in line with the manufacturer’s claim that the average nicotine content does not exceed 3.5 mg? Use a 0.01 level of significance and assume the distribution of nicotine contents to be normal.

Answers

Answer:

0.0793 > 0.01, which means that we have a result in line with the manufacturer's claim.

Step-by-step explanation:

Manufacturer’s claim that the average nicotine content does not exceed 3.5 mg

This means that the null hypothesis is given by:

[tex]H_{0}: \mu = 3.5[/tex]

And the alternate hypothesis is:

[tex]H_{a}: \mu > 3.5[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

3.5 is tested at the null hypothesis

This means that [tex]\mu = 3.5[/tex]

A random sample of 8 cigarettes of a certain brand has an average nicotine content of 4.2 milligrams and a standard deviation of 1.4 milligrams.

This means that [tex]n = 8, X = 4.2, \sigma = 1.4[/tex]

Value of the z-statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{4.2 - 3.5}{\frac{1.4}{\sqrt{8}}}[/tex]

[tex]z = 1.41[/tex]

Pvalue of the test:

We are testing if the mean is higher than 3.5.

The sample mean found is of 4.2, and we have to find the probability of finding a sample mean at least as large as this, which is 1 subtracted by the pvalue of z = 1.41.

z = 1.41 has a pvalue of 0.9207

1 - 0.9207 = 0.0793

0.0793 > 0.01, which means that we have a result in line with the manufacturer's claim.

Simplify
8(10 m)
80 + m
18 m
80 m
810 m

Answers

80m, you kind of distribute so 8 times 10m is 80m


What is the area of the parallelogram
shown above?
[?] square feet

Answers

Answer:

299 square feet

Step-by-step explanation:

Area of a parallelogram = base × height

Base = 23 ft

Height = 13 ft

Note: the other length, 15 ft is not needed in calculating area of the parallelogram. All we need is just the length of the base and the height.

Area of the parallelogram shown = 23 × 13

Area = 299 ft²

-4x = 16

a -64




b 4




c 20




d-4

Answers

-4× = 16 answer: -4

Step-by-step explanation:

-4 × -4 = 16

When calculating simple probability,
what goes in the numerator and what
goes in the denominator?
Please.

Answers

Answer:

The top number in a fraction. Shows how many parts we have. (The bottom number is the Denominator and shows how many equal parts the item is divided into.)

Step-by-step explanation:

what is the value of x? Hiking trails oak trail 125 degrees. pine trail x degrees. ash trail.​

Answers

The value of x is 55.

write an equation in point-slope form of the line that passes through the point (3, 5) and has a slope or -1

Answers

Answer:

y = -x + 8

Step-by-step explanation:

m = -1  ; x1 = 3 ; y1 = 5

Slope point form: y - y1 = m(x -x1)

y - 5 = -1(x - 3)

y -  5 = -1x - 3 *(-1)

y - 5 =-x + 3

    y =  -x + 3 + 5

     y = -x + 8

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