A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 5 students' scores on the exam after completing the course: 16, 21, 22, 12, 22
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

Answers

Answer 1

Answer:

The critical value used is [tex]T_c = 2.132[/tex]

The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).

Step-by-step explanation:

Before building the confidence interval, we need to find the sample mean and the sample standard deviation.

Sample mean:

[tex]\overline{x} = \frac{16+21+22+12+22}{5} = 18.6[/tex]

Sample standard deviation:

[tex]s = \sqrt{\frac{(16-18.6)^2+(21-18.6)^2+(22-18.6)^2+(12-18.6)^2+(22-18.6)^2}{4}} = 4.45[/tex]

Confidence interval:

We have the standard deviation for the sample, so the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So

df = 5 - 1 = 4

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 4 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.132. The critical value used is [tex]T_c = 2.132[/tex]

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.132\frac{4.45}{\sqrt{5}} = 4.243[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 18.6 - 4.243 = 14.357

The upper end of the interval is the sample mean added to M. So it is 18.6 + 4.243 = 22.843.

The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).


Related Questions


If you get a raise from $12 per hour to $15 per hour, what is the percent change?

Answers

Answer:

25%

Step-by-step explanation:

Formula to calculate the percent change :-

Change in distance from $12 per hour to $15 per hours = 15-12=3 per hour

Previous value = $12 per hour

Now, the percent change will be :_

Hence,  the percent change for  from $12 per hour to $15 per hour= 25%

(I copied this answer from JeanaShupp from question-11653373 [no links])

The volume of a rectangular prism (shown below) is 48x^3+56x^2+16x Answer the following questions:
(1) What are the dimensions of the prism?
(2) If x = 2, use the polynomial 48x^3+56x^2+16x to find the volume of the prism.
(3) If x = 2, use the factors found in part a to calculate each dimension.
(4) Using the dimensions found in part c, calculate the volume. Show all work.

Answers

Answer:

(a)

[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]

(b)

[tex]P(2) = 640[/tex]

(c)

[tex]Length= 16[/tex]

[tex]Width = 8[/tex]

[tex]Height =5[/tex]

(d)

[tex]Volume = 640[/tex]

Step-by-step explanation:

Given

[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]

Solving (a): The prism dimension

We have:

[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]

Factor out 8x

[tex]P(x) = 8x(6x^2 + 7x + 2)[/tex]

Expand 7x

[tex]P(x) = 8x(6x^2 + 4x + 3x + 2)[/tex]

Factorize

[tex]P(x) = 8x(2x(3x + 2) +1( 3x + 2))[/tex]

Factor out 3x + 2

[tex]P(x) = 8x(3x + 2)(2x + 1)[/tex]

So, the dimensions are:

[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]

Solving (b): The volume when [tex]x = 2[/tex]

We have:

[tex]P(x) = 48x^3 + 56x^2 + 16x[/tex]

[tex]P(2) = 48 * 2^3 + 56 * 2^2 + 16 * 2[/tex]

[tex]P(2) = 640[/tex]

Solving (c): The dimensions when [tex]x = 2[/tex]

We have:

[tex]Length = 8x\\Width = 3x + 2\\Height = 2x + 1[/tex]

Substitute 2 for x

[tex]Length=8*2[/tex]

[tex]Length= 16[/tex]

[tex]Width = 3*2+2[/tex]

[tex]Width = 8[/tex]

[tex]Height = 2*2 + 1[/tex]

[tex]Height =5[/tex]

So, we have:

[tex]Length= 16[/tex]

[tex]Width = 8[/tex]

[tex]Height =5[/tex]

Solving (d), the volume in (c)

We have:

[tex]Volume = Length * Width * Height[/tex]

[tex]Volume = 16 * 8 * 5[/tex]

[tex]Volume = 640[/tex]

?
What is the equation of a parabola whose focus is (-4, -1)
and whose directrix is
y = -5?

y = + x – 1
8
o
y = -

--X+1
8
y?
x =
+ у - 1
8
y2
X = -
8 Y+1

Answers

Answer:

1st option,

y = x²/8 + x - 1

Answered by GAUTHMATH

PLS HELP
Find an equation of the line with a y-intercept of -3 and an x-intercept of -4.5

Answers

Answer:

y = - [tex]\frac{2}{3}[/tex] x - 3

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

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

with (x₁, y₁ ) = (0, - 3) and (x₂, y₂ ) = (- 4.5, 0 ) ← coordinates of intercepts

m = [tex]\frac{0-(-3)}{-4.5-0}[/tex] = [tex]\frac{0+3}{-4.5-0}[/tex] = [tex]\frac{3}{-4.5}[/tex] = - [tex]\frac{2}{3}[/tex]

The line crosses the y- axis at (0, - 3 ) ⇒ c = - 3

y = - [tex]\frac{2}{3}[/tex] x - 3 ← equation of line

A random number generator is used to create a list of 300 single digit numbers

Answers

What are we trying to find?

Is 3.6 a real number

Answers

Yes
All numbers are real

How many times greater is
6.6 x 10^10
than
3 x 10^7
2.2
22
1000
2200

Answers

Answer:

2,200

Step-by-step explanation:

6.6 x 10^10

= 66,000,000,000

3 x 10^7

= 30,000,000

66,000,000,000 ÷ 30,000,000

2,200

Answer:

2200.

Step-by-step explanation:

6.6 / 3  *  10^10/10^7

= 2.2 * 10^3

= 2200

Find the standard deviation for the following group of data items.
9, 11, 11, 16

Answers

The standard deviation for the given data items is 2.6

The standard deviation of the given data items can be calculated by taking the square root of the variance.

Variance is a measure of variability and it is calculated by taking the average of squared deviations from the mean.

Hence, we will first determine the mean of the given data items.

Mean is simply the average of the numbers.

Therefore mean of the given data items is

[tex]Mean = \frac{9+11+11+16}{4}[/tex]

[tex]Mean = \frac{47}{4}[/tex]

Mean = 11.75

Now, for the variance of the data

[tex]Variance = \frac{(9-11.75)^{2}+(11-11.75)^{2}+(11-11.75)^{2}+(16-11.75)^{2} }{4}[/tex]

[tex]Variance = \frac{(-2.75)^{2}+(-0.75)^{2}+(-0.75)^{2}+(4.25)^{2} }{4}[/tex]

[tex]Variance = \frac{7.5625+0.5625+0.5625+18.0625}{4}[/tex]

[tex]Variance = \frac{26.75}{4}\\[/tex]

∴ Variance = 6.6875

But,

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

∴Standard deviation  [tex]=\sqrt{6.6875}[/tex]

Standard deviation = 2.586

Standard deviation ≅ 2.6

Hence, the standard deviation for the given data items is 2.6

Learn more on standard deviation here: https://brainly.com/question/18562832

A number has ........... number of factors but ........... number of multiple. ​

Answers

A number has fixed number of factors but infinite number of multiples

Ex:-

Take a number 12

It has factors 1,2,3,4,6,12

It is fixed.

But

It has multiples 12,24,36,48,60...

It is infinite

Hi! I'd appreciate if you could help me on this question.

Liam is buying bottles of soda in packages that contain 8 bottles each. If the total number of sodas Liam bough t was between 45 and 50, how many did he buy? Explain your answer.

Answers

Answer:

48

Step-by-step explanation:

We need to find the multiples of 8

8,16,24,32,40,48

48 is between 45 and 50 so he must have bought 48

Answer:

6 bottles

Step-by-step explanation:

For this question we need to know the multiple of 8 which are:

8 x 1 = 8

8 x 2 = 16

8 x 3 = 24

8 x 4 = 32

8 x 5 = 40

8 x 6 = 48

8 x 7 = 56

There is only one multiple, which is greater than 45 but less than 50, which is 8x6 l.

This means he bought 6 bottles.

Answered by g a u t h m a t h

I need help with C,D,E,F,G thank you

Answers

Answer:

D = 120 Degrees ,  E : x = 14 , F: <JHK = 21, G: Summplementary Angle is 96 Degrees

Step-by-step explanation:

4X+2X = 180

6X=180

X=30

<ABD = 4X = 4(30) = 120

D= 120 degrees
If I am correct

If 40 men working on a U.S. government project can complete the job in 100 hours, how many men would be required to complete the job in 80 hours?

Answers

Answer:50

Step-by-step explanation:(40x100):80

Answer: 50 workers

Let the ratio be

(40×100):80

= 400/80

= 50

Therefore 50 workers will complete the same work in 80 hours.

Must click thanks and mark brainliest

Find the missing segment in the image below

Answers

It should be 75c if I’m not mistaken

Books, and then you have 44+45x=?

Answers

Answer:

45x=-44

x=-44/45

Step-by-step explanation:

is this a free question?

a 800g boulder has a density of 8g/cm^3. What is the volume of the boulder?

Answers

Answer:

Below

Step-by-step explanation:

You can use this formula to calculate the volume of an object

     Volume = Mass / Density

Plugging everything in...

     Volume = 800g / 8 g/cm^3

                   = 100 cm^3

Hope this helps!

The volume of the boulder will be equal to 100 cubic centimeters.

What are volume and density?

A substance's density is defined as its mass per unit volume. The density in other words can be defined as the ratio of mass and volume. Its unit will be kg per cubic meter.

The volume is defined as the space occupied by an object in three-dimensional geometry.

It is given that an 800g boulder has a density of 8g/cm^3. The volume will be calculated by using the formula below:-

Volume = Mass / Density

Volume = 800g / 8 g/cm^3

             = 100 cm^3

Therefore, the volume of the boulder will be equal to 100 cubic centimeters.

To know more about volume follow

https://brainly.com/question/17336041

#SPJ2

Prove that: sec⁴B - sec²B = tan⁴B + tan²B.​

Answers

Step-by-step explanation:

sec⁴B - sec²B = sec²B(sec²B - 1)

= (1 + tan²B)(tan²B)

= tan⁴B + tan²B

= Right-hand side (Proven)

What percentage of area is above the mean on a normal curve?
Group of answer choices

34%

68%

97.35%

50%

Answers

Answer:

z=0

50%

Step-by-step explanation:

Read the image for instructions

Answers

Answer:

4 ther are 4 line symmetery

Answer:

two lines of symmetry

(a vertical and a horizontal)

Find the value of x.
A. 57
B. 72
C. 90
D. 124

Answers

Answer:

90

Step-by-step explanation:

Angle Formed by Two Chords= 1/2(SUM of Intercepted Arcs)

105 = 1/2 (120+x)

210 = 120+x

Subtract 120 from each side

210-120 = x

90 =x

The value of  Intercepted Arcs x will be 90. so option C is correct.

What is the relation between line perpendicular to chord from the center of circle?

If the considered circle has center O and chord AB, then if there is perpendicular from O to AB at point C, then that point C is bisecting(dividing in two equal parts) the line segment AB.

Or

|AC| = |CB|

Angle Formed by Two Chords= 1/2 (Sum of Intercepted Arcs)

105 = 1/2 (120+x)

210 = 120+x

Subtract 120 from each side;

210-120 = x

90 =x

Hence, the value of  Intercepted Arcs x will be 90. so option C is correct.

Learn more about chord of a circle here:

https://brainly.com/question/27455535

#SPJ5

Will mercury with a density of 13.6 g/mL float or sink?

Answers

Mercury will sink

(sorry if Im wrong)

Answer:

Sink.

Step-by-step explanation:

Mercury is a quicksilver and hence will sink.

A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 6 students' scores on the exam after completing the course: 6,16,19,12,15,14.
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval.

Answers

Answer:

The critical value is [tex]T_c = 2.5706[/tex].

The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).

Step-by-step explanation:

Before building the confidence interval, we need to find the sample mean and the sample standard deviation:

Sample mean:

[tex]\overline{x} = \frac{6+16+19+12+15+14}{6} = 13.67[/tex]

Sample standard deviation:

[tex]s = \sqrt{\frac{(6-13.67)^2+(16-13.67)^2+(19-13.67)^2+(12-13.67)^2+(15-13.67)^2+(14-13.67)^2}{5}} = 4.4121[/tex]

Confidence interval:

We have the standard deviation for the sample, so the t-distribution is used to solve this question.

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 = 6 - 1 = 5

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.5706, that is, the critical value is [tex]T_c = 2.5706[/tex]

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.5706\frac{4.4121}{\sqrt{6}} = 4.63[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 13.67 - 4.63 = 9.04.

The upper end of the interval is the sample mean added to M. So it is 13.67 + 4.63 = 18.30.

The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).

simplify 27-{ 9+(12-5)÷4} with solution​

Answers

Answer:

16.25

Step-by-step explanation:

first do 12 -5 = 7. then 7/4 = 1.75 then 9+1.75 = 10.75 and finally 27-10.75= 16.25

This is how you do it

Help me please and thank you

Answers

Step-by-step explanation:

jlejej

are u using chrome os

Log 1 with whatever base (except 0) is 0 for any number (except 0) raised to 0th power is 1. And 0 times anything is 0. Answer should be B.

Solve for y. 14y-6(y-3)=22

Answers

Answer:

y=0.5

Step-by-step explanation:

14y-6(y-3)=22

14y-6y+18=22

8y+18=22

8y=4

y=0.5

Then we check our work...

14(0.5)-6((0.5)-3)=22

7-6(-2.5)=22

7+15=22

7+15 does equal 22, so this solution is correct.

[tex]\sqrt{-25[/tex]

Answers

Answer:

±5i

Step-by-step explanation:

sqrt(-25)

We know that sqrt(ab) = sqrt(a) sqrt(b)

sqrt(-1) sqrt(25)

±i 5

±5i

1. In the past, Sam cashed his paycheck each month at Ready Cash, a check cashing service that
charges a 5% fee. He recently opened a checking account at Bank of America so he can now
deposit and/or cash his paycheck without a fee. If Sam is making $28,500 per year, how much will
he save by not going to Ready Cash anymore?

Answers

Step-by-step explanation:

28000 ÷ 100

=280

280 × 5

=1400

I need the answer explained

Answers

Answer:

1.33

Step-by-step explanation:

62 can only be subtracted from 82 once. So 82.46-62 would be 20.46. Since you can't subtract anymore you put a decimal point. 62x3=186 and 20.46-186=1.86 and you can subtract 186-186=0.

Please help!
The quantities x and y are proportional.
x: 4 5 10
y: 10 12.5 25
Find the constant of proportionality (r) in the equation y=rx.

Answers

9514 1404 393

Answer:

  r = 2.5

Step-by-step explanation:

The constant of proportionality can be found by solving the equation for r:

  r = y/x

Then any corresponding values of x and y can be used to find r:

  r = 25/10 = 2.5

The constant of proportionality is 2.5.

What do these have in common

Answers

Answer:

All Equal to 0

Step-by-step explanation:

0 = 0

3 - 3 = 0

0/4 = 0

12 - 3*4 = 0

If the area of a circle is 16π, the circumference of the circle is:

A. 8π
B. 16π
C. 2π
D. 4π

Answers

The answer is option A
Here’s the process
Hope you understand it!
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