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

Suppose Huang invests $720 into an annuity every month for five years. At the end of five years, the account has a balance
of $50,000. How much of this balance is interest?
Round your answer to the nearest dollar.
Do NOT round until you have calculated the final answer.

Answers

Answer:

$6,800

Step-by-step explanation:

The interest earn after 5 years will be $6800.

It is given that Huang invests $720 into an annuity every month for five years and at end of 5 years balance was $50000.

We have to find out the interest earn.

What do you mean by interest ?

Interest is an additional amount of money that is paid by the bank to customer on the amount deposited in his account.

As per the question ;

Investment made by Huang = $720 for five years

At end of five years , account balance = $50000.

So ;

Five years = 60 months

and the investment is an annuity every month for five years.

If Huang invests $720 every month for 5 years then total investment is ;

= $720 × 60

= $43200

And account balance at end of 5 years = $ 50000

So ;

Interest earn will be ;

= $50000 - $43200

= $6800

Thus , the interest earn after 5 years will be $6800.

To learn more about algebra click here ;

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In the small town of Middleton, there are only two restaurants that serve pizza- a small family owned Italian restaurant and a new franchise pizza restaurant. In a recent review of the franchise, a food critic reported that the pizza was delicious as promised. The only negative review that the franchise received from the critic was in reference to the inaccurate delivery time quoted during the online order process. In response to the article, the franchise owner used a program to analyze the online pizza orders that took place during the week before the review. He chose to track the orders at 6pm each day. He recorded his results in the frequency table below. Monday Tuesday Wednesday Thursday Friday On Time ||| || Late | ||| |||| Use the frequency table to create a box and whisker plot of the On Time data values. In your final answer, include all calculations necessary to create the box and whisker plot. Use the frequency table to create a box and whisker plot of the Late data values. In your final answer, include all calculations necessary to create the box and whisker plot.

Answers

Step-by-step explanation:

1.

Yes , the data franchise owner is collecting, will be helpful in order to counter the criticism from the critic. As he has a record for every delivery they are making on daily basis.

2.

The scenario is that for every fifth customer , the owner cross the four lines he makes. Thus a pack of five and easy to remember. As the data on regular week days is less, As can do the same for the third customer. Crossing the 2 lines for 3rd customer.

3.

With this provision of crossing the third customer, the owner can have a better check on the late delivery. As it will bring in his notice earlier as compared to fifth crossing.

4.

With the data as provided in the table, we can come to the conclusion that on weekends , i.e. both on time delivery and late deliveries are high in numbers. It must be because of high demand on that days. So owner must make some provision like hiring some more delivery boys for weekend in order to reduce the late deliveries.

Answer:

Can I get brainliest please??

Step-by-step explanation:

For each ordered pair, determine whether it is a solution to y=6.

Answers

Answer:

yes

no

yes

no

if their is a 6 in the y spot of the coordinate than it is a yes

In a certain clothing store 6 shirts and 3 ties cost $79.50 and 3 shirts and 2 ties cost $41 determine the cost of each shirt

Answers

9514 1404 393

Answer:

  $12 for each shirt

Step-by-step explanation:

If we let 's' and 't' represent the costs of a shirt and tie, respectively, then we can write the general form equations ...

  6s +3t -79.50 = 0

  3s +2t -41.00 = 0

The solution for s can be found using the "cross multiplication" technique.

Differences of products can be formed:

  d1 = (6)(2) -(3)(3) = 3

  d2 = (3)(-41) -(2)(-79.50) = 36

Then we have ...

  1/d1 = s/d2   ⇒   s = d2/d1 = 36/3 = 12

The cost of each shirt is $12.00.

___

2 ties cost 41-36 = 5, so each one is $2.50.

_____

Additional comment

The use of simple elimination on this set of equations would eliminate the s-variable, so would mean additional work to find s after finding t. The t-variable could be eliminated by multiplying one equation by one coefficient, and the other by a different coefficient. As long as we're doing that amount of work, we may as well do just enough cross-multiplication to get the one answer we need. This is where the "cross-multiplication" method of solution comes in handy.

This method solves the general-form equations ...

ax +by +c = 0dx +ey +g = 0

by considering the two rows of coefficients:

a, b, c, ad, e, g, d

Then differences of cross-products are formed in adjacent columns:

  d1 = ae -db

  d2 = bg -ec

  d3 = cd -ga

The solutions are ...

  1/d1 = x/d2 = y/d3   ⇒   x = d2/d1, y = d3/d1

John shared 3 cookies with 4 friends. What fraction of a cookie did each friend recieve?

Answers

Answer:

0.75 .................

Because the dividend is the same for all three expressions the larger the Divisor the__the quotient
Worth 100 points false info or just to take the points you will be reported

Answers

I really need these points thx a lot skim it would be 100 divisor because the quotient

Cecilia invested 12,500 in an account that compounds quarterly at 2%. How much money is in her account after 4 years

Answers

6 persent

75,000 infour year's

follow me

nice study

I think 22400 mainly because i did the calculation

12500 * .2 4 times and got that answer.

I would appreciate if someone could help me with this problem and answer it I will give you a brainlist :)

Answers

To me from the picture, all sides look the same. so I’m guessing it’s probably 11

The mathematics faculty at a college consists of 7 ​professors, 4 associate​ professors, 4 assistant​ professors, and 6 instructors. If one faculty member is randomly​ selected, find the probability of choosing a professor or an instructor.

Answers

Answer:

0.619 = 61.9% probability of choosing a professor or an instructor.

Step-by-step explanation:

A probability is given by the number of desired outcomes divided by the number of total outcomes.

In this question, we have that:

7 + 4 + 4 + 6 = 21 members

7 + 6 = 13 professors or instructors.

Find the probability of choosing a professor or an instructor.

p = 13/21 = 0.619

0.619 = 61.9% probability of choosing a professor or an instructor.

How many triangles can be constructed with angles measuring 110°, 50°, and 20°?


0

1

more than one

Answers

9514 1404 393

Answer:

  (c)  more than one

Step-by-step explanation:

The shape of the triangle is specified by its angles, but not its size. An infinite number of triangles of various sizes can be constructed with those angles. The appropriate choice is ...

  more than one

4.01 ESSENTIAL QUESTIONS
How do you use the distance formula and slope formula to classify a
quadrilateral?
How do you use the distance formula and slope formula to classify a triangle?
How do you use the distance formula and slope formula to prove properties of
polygons?

4.02 ESSENTIAL QUESTIONS
How do you use the slope to prove lines are parallel or perpendicular?
How do you write an equation of a line so that it is parallel or perpendicular to a
given point?
How do you use parallel and perpendicular lines to solve real-world problems?
4.03 ESSENTIAL QUESTIONS
How do you divide a segment into given ratios?

How do you use coordinates to find the perimeter and area of polygons?

Answers

Answer:

You use distance and slope formula to classify a quadrilateral by using the x and y coordinates of the quadrilateral. Boom

Step-by-step explanation:

Ava swam for 154 minutes during her first week of vacation. In her two weeks of vacation, she swam for a total of 357 minutes. How many more minutes did she swim for in the second week than in the first week?
Sort the information from the problem. What do we know? What do we need to figure out?

Answers

Answer:

203 more minutes

We know she swam 154 min in first week.

And in two weeks she swam 357 minutes.

We need to figure out x (total of minutes swam in week two)

So do 357=x+154

Subtract 154 from both sides

x=203

Hope this helps

Find the area of the square.
A =
m4
2

Answers

Area of square = side^2
The side is 1/3
1/3^2 = 1/9
The area would be 1/9m^2

The population of a city decreases by 4% per year. If this year's population is 171,000, what will next year's population be, to the nearest individual?

Answers

How I usually find % is in the calculator I put the number im trying to find the percent of so in this case 171,000 and I multiply that by .4 in the calculator so I would put in 171,000*.4 and get 68,400 but that’s not the answer because you have to get rid of the last number so 4% of 171,000 is 6,840 then you subtract that from 171,000 and that’s your answer I got 164,160 I hope this helps :)

Determine whether the function is periodic. If it is periodic, find the period. f(x)=7sin^3x a. 2pi b. 4pi c. Not periodic d. pi

Answers

It’s not periodic hope this helps

Help please question in picture

Answers

Answer:

220

Step-by-step explanation:

Area of square=8*20=160

Area of triangle=(6*20)/2=60

160+60

Answer:

220 units²

I'm sure this is the answer!

Pls help ignore my answers :v.

Answers

so u r already finished? don't post it next time

What is the equation of the line that is the perpendicular bisector of the segment
with (10,-15) and (-10, 25) as endpoints?
y= kx + 10
y= kx + 5
y= -x + 10
y = 2x + 5

Answers

Answer:

y= kx + 5

Step-by-step explanation:

Perpendicular bisector passes through the midpoint of the line.

The midpoint is:

x = (10 - 10)/2 = 0y = (-15 + 25)/2 = 5

Slope of the line:

m = (25 - (-15))/(-10 - 10) = -2

The line perpendicular to this has to have a slope of 1/2 as perpendicular lines have opposite-reciprocal slopes.

Use point-slope form and point (0, 5) to find the equation of the line:

y - 5 = 1/2(x - 0)y = 1/2x + 5

Correct option seem B as others don't match ours

Please Help me Due in 2 Mins

Answers

the correct answer is 50 + 10n . hope this helps!

The Northwood Clock Tower measures 193 meters tall. Dante is creating a scale model of this building using the scale 75 meters : 1 meter.

To the nearest tenth of a meter, what will be the height of the scale model?

Answers

Step-by-step explanation:

Height of real/height of scale=ratio of scale

193/x=75/1

x=2.6

Hope that helps :)

what is the answer to these questions?

Answers

a=3
b=28
c=3.5
d=8.75
e=75

Find the area of the shaded sector.
158°

Answers

Answer:

120 degree in a while and I am fan of the African American women who have served and are fight with you and I am fan of these days and then I will be there in a few days ago y I love u too

Step-by-step explanation:

fftt fight for you to be a good day at work and you are so cute and I am fan of these people are so cute and I am fan of these game and my name was on the phone with my mom is going to be a good day at add me on the phone with my mom is going to be a good day at work and you are so t I don't know what I said it will be there in a few days ago I got the job at the end of my favorite thing in life that is the best thing that I have to be a good day at work and you are so sweet to say that I have to go back to the for us to be a good day at work and I'm so excited about this one is it a Main St apt c u at work and you are not a bad mood today so I can do it for me to come back in my head and I am fan and I am fan on my is on the phone and it is not a type of settlement of the African American women who have participated and are you doing today I am so proud of u and I am fan on my is on the phone number and you can do it for me to come

Brainliest for correct answer

Answers

D hope this helps xx

The ratio of red cars to blue cars in a parking lot was 5 : 3. If there were 40 red cars, how many blue cars were there?

Answers

Answer:

24 blue cars

Step-by-step explanation:

In this problem, one is given the ratio of red to blue cars in the parking lot. One is given the actual number of red cars, and one is asked to find the number of blue cars. One can set up a proportion; ratio to actual, then solve to find the number of actual blue cars using the method of cross-products. One can set up the proportion using the ratios, but it is easier to express the proportion as the equality of two fractions. Thus, the following equation can be formed, let the parameter (x) represent the actual amount of blue cars;

[tex]\frac{red}{blue}= \frac{5}{3} = \frac{40}{x}[/tex]

Cross products,

[tex]5x = 120[/tex]

Inverse operations,

[tex]x = 24[/tex]

What is the slope of the line through (-1, 8) (3, -4)

Answers

Answer:

D. -3

Step-by-step explanation:


What is the value of x in trapezoid ABCD?

Answers

Answer:

15

Step-by-step explanation:

answer (10-4)x4+8 and i will give u brainlyest and 100pts :>>

Answers

Answer:

(10-4)*4+8

=6*4+8

=24+8

=32

Answer:

32

Step-by-step explanation:

Following PEMDAS we first do the stuff in the parentheses and we get [tex]6x4+8[/tex]

Then since there are no exponents, we go straight to doing the multiplication and division, which leaves us with [tex]24+8[/tex].

Finally when we add the last 2 terms together we get our answer of 32.

Hope this helps!

A fish aquarium is 3 ft long, 2 ft wide, and 2 ft high. What is the volume of the aquarium?

ANSWER ASAP I DONT HAVE MUCH TIME

Answers

I Believe It Is 12ft

A jacket was originally $284. It is discounted 20%, but doesn’t sell, so it is discounted again by 20% off the sale price. Finally, after sitting in the store for 6 months, it is marked as clearance, at 50% of the lowest sale price. What is the clearance price of the jacket?

Answers

113.60




that’s the answerrrr

mrs shalini asked her students to draw pictures of their home. 17/30 used color pencils and 11/30 used crayons for coloring. what fraction of the class used either color pencils or crayons?

Answers

Answer:

23/25 of the class used either color pencils or crayons

Step-by-step explanation:

56% used color pencils

36% used crayons

36% + 56% = 92%

turn 92% into a fraction = 92/100

simplify = 23/25

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