A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following results. T
oday 5 Years Ago Mean 82 88 Variance 112.5 54 Sample Size 45 36
The standard deviation of the difference between the means of the two populations is
A) 12.9
B) 9.3
C) 4
D) 2

Answers

Answer 1

Answer: D) 2

Step-by-step explanation:

The standard deviation of the difference between the means of the two populations is given by:-

[tex]S.E.=\sqrt{\dfrac{\sigma^2_1}{n_1}+\dfrac{\sigma^2_2}{n_2}}}[/tex]

where [tex]n_1[/tex]= sample size of population 1

[tex]n_2[/tex]= sample size of population 2

[tex]\sigma^2_1[/tex]= variance of population 1

[tex]\sigma^2_2[/tex]= variance of population 2

As per given,

[tex]S.E.=\sqrt{\dfrac{112.5}{45}+\dfrac{54}{36}}}\\\\=\sqrt{4}\\=2[/tex]

Hence, the correct option is D) 2.


Related Questions

Write an expression showing 5 less than the number K

Answers

Answer:

K-5

Step-by-step explanation:

Five less than K would be K-5.

Grandma received 0.25 liters of medicine from her doctor. The directions asked her to take one teaspoonful 3 times daily until it is finished. A full teaspoon has a capacity of 4 ml. Grandma started taking her medicine on November 20th. What date should the medicine finish?

Answers

Answer:

Dec 10

Step-by-step explanation:

0.25 liter = 250 ml

4 ml * 3 = 12 ml

250/12 = 20.83 days

Nov 20 - Nov 30: 11 days

Dec 1 - Dec 9: 9 days

On December 9, she can still take her 3 doses.

By December 9, she will have taken 12 ml per day for 20 days for a total of 240 ml. She has 10 ml left for Dec 10th.

On Dec 10, she will take 2 doses of 4 ml and 1 dose of 2 ml, and she will finish the medicine.

Complete the sentence.
9 is 36% of ??

Answers

Answer:

25

Step-by-step explanation:

Ratios:

[tex]\frac{36}{100} =\frac{9}{x} \\\\36x=900\\x=25[/tex]

Double check:

25(0.36) = 9

Identify the following parts of an introductory paragraph in the order that they should appear.

First:

Second:

Third:


Answer Choises

hook, context, thesis


Have a nice day!

Answers

Answer:

1st-Hook

2nd- Thesis statement

3rd-context

Step-by-step explanation:

1- hook is to attract the reader, like a line to a song that is catchy! you want to draw the reader in!

2- Thesis statment

3- give context on the thesis statement! to further prove.

good luck

He measured the pool’s dimensions to be 15 feet long by 35 feet wide. The actual dimensions of the pool are 14.5 feet by 34.75 feet. Find Jack’s percent error to the nearest percent.

Answers

Answer:

Percent error = -4.02 (Approx.)

Step-by-step explanation:

Given:

Estimated pool dimension = 15 ft long and 35 ft wide

Actual pool dimension = 14.5 ft long and 34.75 ft wide

Find:

Percent error

Computation:

Area of Estimated pool = 15 x 35

Area of Estimated pool = 525 ft²

Area of Actual pool = 14.5 x 34.75

Area of Actual pool = 508.875 ft²

Percent error = [(Actual - Estimated) / Estimated]100

Percent error = [(508.875 - 525) / 525]100

Percent error = [(-21.125) / 525]100

Percent error = -4.02 (Approx.)

At her new job, Laura is getting paid $18.35 per hour. If she is scheduled to work 12 hours on Saturday, how much will she earn?

Answers

Answer:

$220.2

Step-by-step explanation:

Multiply 18.35 to 12

What are the ordered pairs of the
solutions for this system of equations?
f(x) = x2 – 2x + 3; f(x) = –6x
(-3, [?]); ([ ]), ([ ])

Answers

Answer:

[tex] {x}^{2} - 2x + 3 = - 6x \\ = {x}^{2} - 2x + 6x + 3 = 0 \\ \\ = {x}^{2} + 4x + 3 = 0 \\ = (x + 1)(x + 3) \\ = x = - 1and \: x = - 3[/tex]

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]

what is the givien x-value that can used to make the prediction​

Answers

Answer:

haha there is no question

Step-by-step explanation:

aww please check if there are more expect around to answer

What is the arc measure of major arc \stackrel{\large{\frown}}{ACB}
ACB

A, C, B, start superscript, \frown, end superscript on circle PPP in degrees?

Answers

Answer:

286°

Step-by-step explanation:

A circle is the locus of a point such that its distance from a fixed point (known as the center) is always constant. This distance is known as the radius of the circle.

A major arc is an arc larger than a semicircle, therefore its measure is greater than 180°. A minor arc is an arc smaller than a semicircle, therefore its measure is less than 180°.

The arc measure of [tex]\stackrel{\large{\frown}}{ACB}=angle\ about\ a\ point-\stackrel{\large{\frown}}{AB}[/tex]

The arc measure of [tex]\stackrel{\large{\frown}}{ACB}=360-74=286^o\\[/tex]

Write the proportion.
8.5 hours is to 3.4 hours as
7.0 hours is to 2.8 hours?

Answers

8.5/3.4 = 7.0/2.8
hope this helps

A 3-column table with 4 rows titled 90-Day Forecast. Column 1 is labeled Weather Type with entries wind, rain, clouds, sunshine. Column 2 is labeled Predicted frequency with entries 9, 18, 27, 36. Column 3 is labeled Observed frequency with entries 12, 15, 33, 30.
The table shows the results of the experiment to determine the 90-day weather forecast. How does the experimental probability compare to the theoretical probability?

The theoretical probability for rain is 1/5. The experimental probability for rain is
.
The actual weather is
the theoretical probability.

Answers

1/6

approximately the same as

Answer:

✔1/6

✔ approximately the same as

Step-by-step explanation:

Here's proof

An insect population triples every 4 months. If the population started out with 24 insects, how many
insects would there be in 16 months?

Answers

Answer:

After 16 months there will be a population of 1,944 insects.

Step-by-step explanation:

Since an insect population triples every 4 months, if the population started out with 24 insects, to determine how many insects would there be in 16 months, the following calculation must be performed:

X = 24 x 3 ^ (16/4)

X = 24 x 3 ^ 4

X = 1,944

Thus, after 16 months there will be a population of 1,944 insects.

a group of students collected old newspapers for a recycling project. the data shows the mass, in kilograms, of old newspapers collected by each student.

23, 35, 87, 64, 101, 90, 45, 76, 105, 60, 55
98, 122, 49, 15, 57, 75, 120, 56, 88, 45, 100.

A.) Find the range of the mass of the newspapers collected.
B.) Find the interquartile range.

Answers

Answer:

A. 107 kg

B. 49 kg

Step-by-step explanation:

Find the average number of people in these cities: New York, Philadelphia, Chicago and Detroit a. 3.35 million b. 40 million. C. 4.0 million d. 33.million

Answers

Answer:

The answer is maybe going to be D which is 33 million

Step-by-step explanation:

New york is a big city

Find the value of x.
log 3 X= 4
OA. 7
OB.
12
Oc.
27
OD
81

Answers

Answer:

OB

Step-by-step explanation:

when we multiple 4 by 3 because they are like terms they give us 12

Real word example where a
piecework function might be used

Answers

9514 1404 393

Explanation:

Garment factory: workers may get paid by the number of pieces they complete.

__

Wood chopping: the worker gets paid by the number of cords of wood they produce, not by how long it takes.

__

Haircut -- the cost is the same (for the same type haircut) even if more time is spent

____

The above are instances where an individual worker gets paid by the piece they produce. There are numerous instances of companies getting paid by the job, regardless of the length of time or the quantity of materials required to do the job.

Lawn mowing -- the price is fixed each time the crew mows the lawn

Oil Change -- the cost of changing the oil in the car is not dependent on the time it takes or the amount of oil used

Car wash -- a fixed price is paid each time (at an automatic car wash)

50+12÷3×5−2 do this for 25 points fast please (use PEMDAS)

Answers

Answer:

68

Step-by-step explanation:

Point B is located at _____.
(-3, 0) (3, 0) (0, 3) (0, -3)

Answers

Answer:

3, 0

Step-by-step explanation:

first number is on the horizontal line and the second number on the vertical line

Answer: (3, 0)

Step-by-step explanation: To get to point B from the origin, we move 3 units to the right and 0 units up or down so our point has the coordinates (3, 0).

Remember to always go left or right first, which represents x,

then up or down, which represents y.

4) What is the perimeter of a square that has an area of 262.44 feet?

Answers

Answer:

64.8 ft

Step-by-step explanation:

A square has all its sides equal

Therefore to get one side from its area is simply finding the square root of its area

√262.44=16.2ft

Having the one side then perimeter= to the four equal sides × the dimensions of one side

=4×16.2

=64.8 ft

What is the area of △STU rounded to the nearest tenth?

Answers

Answer:

38.7 units²

Step-by-step explanation:

4.6/SV = SV/8.1

SV² = 37.26

SV = 6.1

area = 1/2(8.1)(6.1) + 1/2(4.6)(6.1) = 38.7 units²


Help last assignment for the semester

Answers

90 degrees I think sorry

Answer:

b=2sqrt14

A=33.7°(rounded to nearest tenth)

B=56.3°

Step-by-step explanation:

Pythagorean theorem= sqrt(c^2-a^2)=sqrt(9^2-5^2)=2sqrt14

angleA= sin^-1(5/9)=33.7°

angleB=90°-33.7°= 56.7°

Hopefully that makes sense

Graph this function.

F(x)= -1/3x + 8

I need help ASAP! The -1/3x is a fraction. Can anyone help?

Answers

Step-by-step explanation:

Rewrite the function as an equation.

[tex]y = - \frac{x}{3} + 8[/tex]

Rewrite in slope-intercept form.

[tex]y = - \frac{1}{3} x + 8[/tex]

Use the slope-intercept form to find the  slope  and  y-intercept.

Slope : - 1/3

y-intercept: (0,8)

Any line can be graphed using two points. Select two x values, and plug them into the equation to find the corresponding y values.

Graph the line using the slope and the y-intercept, or the points.

Square 1 has a area of 24 square units if square 2 is half the size what is the ratio of the area of square one to square two?

Answers

Answer:

Step-by-step explanation:

I'm going to guess that 1/2 the size means the sides are 1/2 the size.

Square 1 has an area of 24. The sides are s, so the area is found by using s^2

The second square is made from sides that are 1/2 s

Area = 1/2 s * 1/2 s

Area = 1/4 s^2

Area 1 / area 2 = 24 / x^2 = s^2 / 1/4 s^2 =  1/0.25

what type of function is shown on the table below​

Answers

Answer:

x-fx-x*x

Step-by-step explanation:

sorry for the bad picture. I’m confused on how to solve this as it feels like I don’t have all the information needed.

Answers

hey can you help me with my homework
Answer is B -1

Solution solved below plus sorry for the bad writing.

Roller skates that usually sells for $125 is on sale for 35% off. Find the sale price.

Answers

Answer:

$81.25

Step-by-step explanation:

First find 35% of 125 which is 43.75

Next subtract 43.75 from 125

Your answer is $81.25

Your round-trip drive to work is 4 1. miles. How many miles do you drive to and from
work in 3 days?
7 3/10
12 3/10
12 9/10
8 3/5

Answers

last one okay bye have a nice day

Help please will mark brainliest!!!

Answers

Answer:

18

Step-by-step explanation:

113.1 approximately. Formula: pi X r^2 X height

At a school carnival, 51 out of 68 tickets sold were early-admission tickets. What percentage of the tickets were early-admission tickets?

Answers

51/68x100= 75%

early admissions = 75%
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