A psychology professor assigns letter grades on a test according to the following scheme. A: Top 14% of scores B: Scores below the top 14% and above the bottom 65% C: Scores below the top 35% and above the bottom 16% D: Scores below the top 84% and above the bottom 9% F: Bottom 9% of scores Scores on the test are normally distributed with a mean of 68.4 and a standard deviation of 9.7. Find the numerical limits for a B grade. Round your answers to the nearest whole number, if necessary.

Answers

Answer 1

Answer:

The numerical limits for a B grade are 72 and 79, that is, a score between 72 and 79 results in a B grade.

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.

Scores on the test are normally distributed with a mean of 68.4 and a standard deviation of 9.7.

This means that [tex]\mu = 68.4, \sigma = 9.7[/tex]

Find the numerical limits for a B grade.

Below the 100 - 14 = 86th percentile and above the 65th percentile.

65th percentile:

X when Z has a p-value of 0.65, so X when Z = 0.385.

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

[tex]0.385 = \frac{X - 68.4}{9.7}[/tex]

[tex]X - 68.4 = 0.385*9.7[/tex]

[tex]X = 72[/tex]

86th percentile:

X when Z has a p-value of 0.86, so X when Z = 1.08.

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

[tex]1.08 = \frac{X - 68.4}{9.7}[/tex]

[tex]X - 68.4 = 1.08*9.7[/tex]

[tex]X = 79[/tex]

The numerical limits for a B grade are 72 and 79, that is, a score between 72 and 79 results in a B grade.


Related Questions

18. Which of the following is true for a circle that has a circumference of approximately 75 feet?
O The diameter is approximately 12 feet.
O The radius is approximately 12 feet.
O The radius is approximately 12 square feet.
O The diameter is approximately 12 square feet.

Answers

Answer:

A) The diameter is approximately 12 feet.

Step-by-step explanation:

C= piD

sq ft would be wrong bc this is not talking ab area

Which of the following displays cannot be used to compare data from two different sets?

Answers

Answer:

Scatter plot charts are good for relationships and distributions, but pie charts should be used only for simple compositions — never for comparisons or distributions.

Which expression is equivalent to 3(x - y) + y? 3x - 4y 3x - 3y 3x - 2y 3(x - 2y)

Answers

9514 1404 393

Answer:

  (c)  3x - 2y

Step-by-step explanation:

Use the distributive property to eliminate parentheses, then collect terms.

  3(x -y) +y = 3x -3y +y = 3x +(-3+1)y = 3x -2y

Now we have to find,

The expression which is equivalent to,

→ 3(x - y) + y

Let's get the solution,

→ 3(x - y) + y

→ 3x - 3y + y

→ 3x - 2y

Hence, required expression is 3x - 2y.

What number can go in the box to make the number sentence true?
6 + 0 = 10
0.
4.
6.
10.

Answers

I believe it would be 4 lil man

Fraces bonitas para decirle a tu nv?

minimo 6

Answers

Answer:

it's. is now the MA plz I miss you

si pudiera escoger entre vivir eternamente y vivir dos veces

yo escogeria vivir dos veces porque vivir una vida eterna sin ti a mi lado seria el mayor sufrimiento, ahora vivir dos veces me dejaria tranquilo porque despues del final de mi vida podria volver a encontrarme contigo y vivir todos los momentos bellos una vez mas y eso seria un sueño volviendose realidad

Answer theas question

Answers

(1) Both equations in (a) and (b) are separable.

(a)

[tex]\dfrac xy y' = \dfrac{2y^2+1}{x+1} \implies \dfrac{\mathrm dy}{y(2y^2+1)} = \dfrac{\mathrm dx}{x(x+1)}[/tex]

Expand both sides into partial fractions.

[tex]\left(\dfrac1y - \dfrac{2y}{2y^2+1}\right)\,\mathrm dy = \left(\dfrac1x - \dfrac1{x+1}\right)\,\mathrm dx[/tex]

Integrate both sides:

[tex]\ln|y| - \dfrac12 \ln\left(2y^2+1\right) = \ln|x| - \ln|x+1| + C[/tex]

[tex]\ln\left|\dfrac y{\sqrt{2y^2+1}}\right| = \ln\left|\dfrac x{x+1}\right| + C[/tex]

[tex]\dfrac y{\sqrt{2y^2+1}} = \dfrac{Cx}{x+1}[/tex]

[tex]\boxed{\dfrac{y^2}{2y^2+1} = \dfrac{Cx^2}{(x+1)^2}}[/tex]

(You could solve for y explicitly, but that's just more work.)

(b)

[tex]e^{x+y}y' = 3x \implies e^y\,\mathrm dy = 3xe^{-x}\,\mathrm dx[/tex]

Integrate both sides:

[tex]e^y = -3e^{-x}(x+1) + C[/tex]

[tex]\ln(e^y) = \ln\left(C - 3e^{-x}(x+1)\right)[/tex]

[tex]\boxed{y = \ln\left(C - 3e^{-x}(x+1)\right)}[/tex]

(2)

(a)

[tex]y' + \sec(x)y = \cos(x)[/tex]

Multiply both sides by an integrating factor, sec(x) + tan(x) :

[tex](\sec(x)+\tan(x))y' + \sec(x) (\sec(x) + \tan(x)) y = \cos(x) (\sec(x) + \tan(x))[/tex]

[tex](\sec(x)+\tan(x))y' + (\sec^2(x) + \sec(x)\tan(x)) y = 1 + \sin(x)[/tex]

[tex]\bigg((\sec(x)+\tan(x))y\bigg)' = 1 + \sin(x)[/tex]

Integrate both sides and solve for y :

[tex](\sec(x)+\tan(x))y = x - \cos(x) + C[/tex]

[tex]y=\dfrac{x-\cos(x) + C}{\sec(x) + \tan(x)}[/tex]

[tex]\boxed{y=\dfrac{(x+C)\cos(x) - \cos^2(x)}{1+\sin(x)}}[/tex]

(b)

[tex]y' + y = \dfrac{e^x-e^{-x}}2[/tex]

(Note that the right side is also written as sinh(x).)

Multiply both sides by e ˣ :

[tex]e^x y' + e^x y = \dfrac{e^{2x}-1}2[/tex]

[tex]\left(e^xy\right)' = \dfrac{e^{2x}-1}2[/tex]

Integrate both sides and solve for y :

[tex]e^xy = \dfrac{e^{2x}-2x}4 + C[/tex]

[tex]\boxed{y=\dfrac{e^x-2xe^{-x}}4 + Ce^{-x}}[/tex]

(c) I've covered this in an earlier question of yours.

(d)

[tex]y'=\dfrac y{x+y}[/tex]

Multiply through the right side by x/x :

[tex]y' = \dfrac{\dfrac yx}{1+\dfrac yx}[/tex]

Substitute y(x) = x v(x), so that y' = xv' + v, and the DE becomes separable:

[tex]xv' + v = \dfrac{v}{1+v}[/tex]

[tex]xv' = -\dfrac{v^2}{1+v}[/tex]

[tex]\dfrac{1+v}{v^2}\,\mathrm dv = -\dfrac{\mathrm dx}x[/tex]

[tex]-\dfrac1v + \ln|v| = -\ln|x| + C[/tex]

[tex]\ln\left|\dfrac yx\right| -\dfrac xy = C - \ln|x|[/tex]

[tex]\ln|y| - \ln|x|  -\dfrac xy = C - \ln|x|[/tex]

[tex]\boxed{\ln|y| -\dfrac xy = C}[/tex]

Which of the following is a solution to 2sin2x+sinx-1=0?

Answers

Answer:

270 degrees

Step-by-step explanation:

If you plug in 270 in place of the x's, the function is true!

This is correct for Plate/Edmentum users!! Hope I could help :)

Building A is 170 feet shorter than building B. The total height of the two building is 1490 feet. Find the height of each building.

Answers

Answer:

Building A is 660 feet and Building B is 830 feet

Step-by-step explanation:

Let x represent the height of building B.

Since building A is 170 feet shorter than building B, it can be represented by x - 170.

Create an equation and solve for x:

(x) + (x - 170) = 1490

2x - 170 = 1490

2x = 1660

x = 830

So, the height of building B is 830 feet.

Subtract 170 from this to find the height of building A:

830 - 170

= 660

Building A is 660 feet and Building B is 830 feet

PLEASE HELPPPPPPPPPPP

Answers

Answer:

P(S or T) = 3/4

Step-by-step explanation:

Divide 5x^2+3x-2 by x + 1

Answers

5x + 8

I used long division

what are the zeros of this function?

Answers

Answer:

the Ans is c

Step-by-step explanation:

actually I don't know how to explain


15. Find the x- and y-intercepts for the lineal equation - 3x + 4y = 24

Please explain steps! ❤️

Answers

Answer:

x (-8,0)

y (0,6)

Step-by-step explanation:

at the x-intercept, y = 0

at the y-intercept x=0

sub those values into your equation!

for the x-intercept,

-3x = 24

x = -8

for the y-intercept,

4y = 24

y = 6

Help please guys thanks

Answers

Answer:

5

Step-by-step explanation:

(625 ^2)^(1/8)

Rewriting 625 as 5^4

(5^4 ^2)^(1/8)

We know that a^b^c = a^(b*c)

5^(4*2)^1/8

5^8 ^1/8

5^(8*1/8)

5^1

5

Answer:

[tex]5[/tex]

Step-by-step explanation:

[tex] { {(625}^{2} )}^{ \frac{1}{8} } \\ { ({25}^{2 \times 2} )}^{ \frac{1}{8} } \\ {25}^{4 \times \frac{1}{8} } \\ {5}^{2 \times 4 \times \frac{1}{8} } \\ {5}^{ \frac{8}{8} } \\ {5}^{1} \\ = 5[/tex]

Evaluate z^2−3 z+4 , when z=−4

Answers

Answer:

8

Step-by-step explanation:

=z²-3z+4 when z is 4

=4²-3(4)+4

=16-12+4

=8

It should be -19

I got the answer by plugging it into Desmos scientific calculator.

1. Consider a lottery with three possible outcomes:-$125 will be received with probability 0.2-$100 will be received with probability 0.3-$50 will be received with probability 0.5a. What is the expected value of the lottery

Answers

Answer:

The expected value of the lottery is $80

Step-by-step explanation:

To get the expected value, we have to multiply each outcome by its probability

Then we proceed to add up all of these to get the expected value of the lottery

we have this as ;;

125(0.2) + 100(0.3) + 50(0.5)

= 25 + 30 + 25 = $80

what’s the missing side of the polygons

Answers

Answer:

the missing side is 21!!!!!!!!

i got 21 but i may be wrong :)

find x in this similar triangles

Answers

Answer:

6. x = 4

8. x = 13

Step-by-step explanation:

Using similar triangles theorem,

6. (5+4)/5 = (4x + 2)/(4x + 2 - 8)

9/5 = (4x + 2)/(4x - 6)

Cross multiply

9(4x - 6) = 5(4x + 2)

36x - 54 = 20x + 10

Collect like terms

36x - 20x = 54 + 10

16x = 64

16x/16 = 64/16

x = 4

8. (4x + 13)/20 = 52/16

(4x + 13)/20 = 13/4

Cross multiply

4(4x + 13) = 13(20)

16x + 52 = 260

16x = 260 - 52

16x = 208

x = 208/16

x = 13

Game consoles: A poll surveyed 341 video gamers, and 95 of them said that they prefer playing games on a console, rather than a computer or hand-held device. An executive at a game console manufacturing company claims that the proportion of gamers who prefer consoles differs from . Does the poll provide convincing evidence that the claim is true

Answers

Answer:

proportion of gamers who prefer console does not differ from 29%

Step-by-step explanation:

Given :

n = 341 ; x = 95 ; Phat = x / n = 95/341 = 0.279

H0 : p = 0.29

H1 : p ≠ 0.29

The test statistic :

T = (phat - p) ÷ √[(p(1 - p)) / n]

T = (0.279 - 0.29) ÷ √[(0.29(1 - 0.29)) / 341]

T = (-0.011) ÷ √[(0.29 * 0.71) / 341]

T = -0.011 ÷ 0.0245725

T = - 0.4476532

Using the Pvalue calculator from test statistic score :

df = 341 - 1 = 340

Pvalue(-0.447, 340) ; two tailed = 0.654

At α = 0.01

Pvalue > α ; We fail to reject the null and conclude that there is no significant evidence that proportion of gamers who prefer console differs from 29%

The following data represents the age of 30 lottery winners.

22 30 30 35 36 37 37
37 39 39 41 51 51 54
54 55 57 57 58 58 61
64 68 69 72 74 75 78 79 80

Complete the frequency distribution for the data.

Age Frequency
20-29
30-39
40-49
50-59
60-69
70-79
80-89

Answers

Door key nhfsssrtgfrtgbkoooo your name and number of your name on the card number for you and the name is your
Ages. ==> Frequencies
20-29 ==> 1
30-39 ==> 9
40-49 ==> 1
50-59 ==> 9
60-69 ==> 4
70-79 ==> 5
80-89 ==> 1
(Total 30)

cho f(x)= sign x và g(x) = x(1-x^2). tìm f(g(x))

Answers

Answer:

[tex]f(g(x))= sign(x(1-x^{2})) = sign(x-x^{3})[/tex]

Step-by-step explanation:

what 30 + 30+60+(56)-82=?

Answers

94 is the correct answer for that question

Step-by-step explanation:

30+30+60+56-82=94

Suppose you make napkin rings by drilling holes with different diameters through two wooden balls (which also have different diameters). You discover that both napkin rings have the same height 5h. Use cylindrical shells to compute the volume V of a napkin ring of height 5 h created by drilling a hole with radius r through the center of a sphere of radius R and express the answer in terms of h .

Answers

Answer:

V = 1/6 π ( 5h)^3

Step-by-step explanation:

Height of napkin rings = 5h

Compute the volume V of a napkin ring

let a = 5

radius = r

express answer in terms of h

attached below is the detailed solution

Find the missing length indicated

Answers

Answer:

x = 175

Step-by-step explanation:

A rope is 56 in length and must be cut into two pieces. If one piece must be six times as long as the other, find the length of each piece. Round your answers to the nearest inch, if necessary.

Answers

Answer:

48, 6

Step-by-step explanation:

The ratio of the pieces is 6 to 1

Add them together to get the total

6+1 = 7

Divide the total length by 7

56/7 = 8

Multiply the ratios by 8

6*8 = 48

 1*8 = 6

The peices are 48 and 6

If 800g of a radioactive substance are present initially and 8 years later only 450g remain, how much of the substance will be present after 16 years? (Round answer to a whole number)

Answers

A=Pe^(rt)

P = 800g

t = 8 years

A = 450g

r = This is what we will try and find to start with

450=800e^(r*8)

After running the math through a calculator, we end with r = -0.07192

Now we just re-input this information into our equation: A=800e^(-0.07192*16)

A=800e^(1.15072)

Now we will re-write the equation using the negative exponent rule:

A = 800 1/e^1.15072

Combine right side:

A = 800/e^1.15072

Then do the math:

A = 253.12709836......

That will give us A = 253 (rounded to the whole number)

I hope this helps! :)

The substance that should be presented after 16 years is 253.

Given that,

If 800g of a radioactive substance are present initially and 8 years later only 450g remain.

Based on the above information, the calculation is as follows:

We know that

[tex]A=Pe^{rt}[/tex]

Here

P = 800g

t = 8 years

A = 450g

[tex]450=800e^{r\times 8}\\\\A=800e^{-0.07192\times 16}\\\\A=800e^{1.15072}\\\\A = 800 \ 1 \div e^{1.15072}\\\\A = 800\div e^{1.15072}[/tex]

A = 253

Therefore we can conclude that the substance that should be presented after 16 years is 253.

Learn more: brainly.com/question/16115373

Help please!! Based on Pythagorean identities, which equation is true ??

Answers

Answer:

Last answer: [tex]cot^{2} \alpha - csc^{2} \alpha = -1[/tex]

sorry couldn't find theata so I just used alpha.

Rate of change or rate of change

A farmer has 80 feet of wire mesh to surround a rectangular pen.
A) Express the area A of the pen as a function of x, also draw the figure of A indicating the admissible values ​​of x for this problem.
B) What are the dimensions of the maximum area pen?

Answers

Answer:

Step-by-step explanation:

A). Let the dimensions of the rectangular pen are,

Length = l

Width = x

Since, farmer has the wire measuring 80 feet to surround the the pen.

Perimeter of the pen = 80 feet

2(l + x) = 80

l + x = 40

l = 40 - x ------(1)

Area of the rectangular pen = Length × width

                                               = lx

By substituting the value of l from equation (1),

Area (A) of the pen will be modeled by the expression,

A = (40 - x)

A = 40x - x²

B). For maximum area of the pen,

Derivative of the area = 0

[tex]\frac{d}{dx}(A)=0[/tex]

[tex]\frac{d}{dx}(A)=\frac{d}{dx}(40x-x^2)[/tex]

         = 40 - 2x

And (40 - 2x) = 0

x = 20

Therefore, width of the pen = 20 feet

And length of the pen = 40 - 20

                                     = 20 feet

Dimensions of the pen should be 20 feet by 20 feet.

Please help on this initial amount problem

Answers

Initial amount: 27,500
Growth
Value of car change 28% each year

When a fridge is imported, a customs value of 10% must be paid for its value. If the value of the fridge after paying the customs value is rs. 55,000/-. What is the value before paying customs duty?

Answers

Answer:

55000×100/90

61,111.111

How would yo expand ln (1/49k)?

Answers

Answer:

Step-by-step explanation:

It depends on whether you mean ln(1/49k) or ln(1/(49k)).

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