Mathematics College

A school district is considering moving the start of the school day at Groveland High from 8:00 a.m. to 9:00 a.m. to allow students to get more sleep at night. They want to estimate how many more hours of sleep teens get if their school starts at 9:00 a.m. compared to teens whose schools start at 8:00 a.m. The district takes random samples of 50 of students from Groveland High and 39 students from Phillips High School, which starts at 9:00 a.m., and surveys them about their sleep habits. The sample mean number of hours of sleep per student at Groveland is 7.1 hours, and the standard deviation is 1.7 hours. At Phillips, the sample mean is 8.3 hours of sleep, with a standard deviation of 1.9 hours. What is the 90% confidence interval for the difference in mean hours of sleep for students at the two high schools

Answers

Answer 1

Answer:

The answer is "[tex]\bold{(7.1-8.3) \pm 1.665 \sqrt{\frac{(1.7)^2}{50}+\frac{(1.9)^2}{39}} }\\\\[/tex]"

Step-by-step explanation:

Given values:

[tex]\bar{x_1}=7.1\\\\\bar{x_2}=8.3\\\\s_1=1.7\\\\s_2=1.9\\\\n_1=50\\\\n_2=39[/tex]

Using formula:

[tex]\to (\bar{x_1} -\bar{x_2}) \pm t \sqrt{\frac{(s_1)^2}{n_1}+\frac{(s_1)^2}{n_2}} \\\\[/tex]

Put the values in the above formula:

[tex]\to (7.1-8.3) \pm 1.665 \sqrt{\frac{(1.7)^2}{50}+\frac{(1.9)^2}{39}} \\\\[/tex]

Related Questions

Can someone help me with this?

Answers

9514 1404 393

Answer:

π/4, 7π/4

Step-by-step explanation:

Adding √2 and dividing by 2 makes the equation ...

cos(θ) = (√2)/2

The first-quadrant solution is ...

θ = arccos((√2)/2) = π/4

The angle in the 4th quadrant with the same reference angle will have the same cosine value.

θ = 2π -π/4 = 7π/4

The two solutions are θ = π/4, 7π/4.

Compare and 1.6. Use <, >, or =.
A. 5/3 = 1.6
B. 5/3 < 1.6
c. 5/3 > 1.5

Answers

Step-by-step explanation:

[tex] \frac{5}{3} = 1 \frac{2}{3} = 1.67[/tex]

Since

[tex]1.67 > 1.6 \: and \: > 1.5[/tex]

C is the answer

You want to buy a pet rabbit that costs $49. You already have $18 and you plan to save $9 per week. If w represents the number of weeks until you have enough money to buy the rabbit, what equation could you use to find the value of w? Use pencil and paper. Explain how you could set up an equation to find the amount of money you should save each week if you want to buy the rabbit in six weeks.

Answers

Answer:

You would need $31 so W=4 and you would have $5 left

Step-by-step explanation:

i did 49 minus 18 which gave me 31 so 9c3 would be 27 so i did 9 times 4 would =36 and if you work for 6 weeks you would have 54 and add 18 to it and you would have $72

sorry if im wrong or late

Harry manages a sales force which sells several products in different sales territories. A random sample of 25 territories were selected and the data is provided in an Excel worksheet labelled Harrys. The variables include total sales credited to the sales representative (Sales), the length of time employed in months (time), the market potential (Poten), the advertising expense for the territory (AdvExp), the market share (Share), the change in market share over the previous three years (Change), the number accounts assigned to the sales representative (accounts), an index representing the workload (work), the rating on the last performance review (rating) and whether it is a star territory (star territories have performed well in the past).
Using the methods discussed in this class, determine the “best” regression model to predict Sales. Write a brief report (less than two pages) summarizing your analysis, including key statistical results, conclusions, and recommendations. Include any appropriate technical material in an appendix.

Answers

Answer:

13,000 i think

Step-by-step explanation:

Which story problem COULD not be solved with a expression 3 1/2 x 1/3

Answers

Answer:

Step-by-step explanation:

Instead of how much she should've had left it should've asked how much did she use.

Please help me with the question

Answers

Answer:

area = 84 m²

Step-by-step explanation:

area = (1/2)(4)(3)(2) + (5)(6) + (6)(3) + (4)(6) = 84 m²

Bananas cost $ 0.59 per pound.Write an equation that could be used to find the total cost,y,of x pounds of bananas.

Answers

I think it is 5 Bc I do and if you got to know so bad

Answer:

Step-by-step explanation:

D is greater than E and less than C.
C and D are opposites.
At least one number is greater than A.

HELP

Answers

Answer:

Step-by-step explanation:

100 POINTS AND DOING BRAINIEST create a factorable polynomial with a GCF of 6 rewrite that polynomial in two other equivalent forms explain how each form was created. Please help

Answers

Answer:

100 point sheeshhh ill take em but i don't have awnsers m8

Need help please and thank you

Answers

Answer:

B is your answer

Step-by-step explanation:

there is none but GOOD LUCK

Which NCAA college basketball conference has the higher probability of having a team play in a college basketball's national championship game? Over the last 20 years, the Atlantic Coast Conference (ACC) ranks first by having a team in the championship game 10 times. The Southeastern Conference (SEC) ranks second by having a team in the championship game 8 times. However, both conferences have had teams in the championship game only one time, when Arkansas (SEC) beat Duke (ACC) 76â€“70 in 1994 (NCAA website, April 2009). Use these data to estimate the following probabilities.

a. What is the probability the ACC will have a team in the championship game?
b. What is the probability the SEC will have team in the championship game?
c. What is the probability the ACC and SEC will both have teams in the championship game?
d. What is the probability at least one team from these two conferences will be in the championship game? That is, what is the probability a team from the ACC or SEC will play in the championship game?
e. What is the probability that the championship game will not a have team from one of these two conferences?

Answers

Answer:

A)P(ACC has a team in the championship game) = 0.5

B)P(SEC has a team in the championship game) = 0.4

C)P(both ACC & SEC having teams in the championship games) = 0.05

D)P(ACC or SEC) = 0.85

E)P(not ACC or SEC) = 0.15

Step-by-step explanation:

A) We are told that in the last 20 years, ACC has had a team in the championship game for 10 times.

Thus;

P(ACC has a team in the championship game) = 10/20 = 0.5

B) SEC has a team in the championship game 8 times in the last 20 years;

Thus;

P(SEC has a team in the championship game) = 8/20 = 0.4

C) since both ACC and SEC have had teams in the championship game for the past 20 years, then;

P(both ACC & SEC having teams in the championship games) = 1/20 = 0.05

D) Addition rule of probability is that;

P(A or B) = P(A) + P(B) - P(A & B)

Applying it to this question, we have;

P(ACC or SEC) = P(ACC) + P(SEC) - P(ACC & SEC)

Plugging in the relevant values, we have;

P(ACC or SEC) = 0.5 + 0.4 - 0.05

P(ACC or SEC) = 0.85

E) from complement rule, we can find the probability that the championship game will not a have team from one of these two conferences.

Thus;

P(ACC not SEC) = 1 - P(ACC or SEC)

P(ACC not SEC) = 1 - 0.85

P(ACC not SEC) = 0.15

..Find the missing number?

Answers

Answer:

The missing number would be 17

Step-by-step explanation:

Answer: I think it’s 7

Step-by-step explanation:

Helppp me plsssssss I need this hel me out

Answers

The equation that models the table is a) y = -4x + 1.

someone please help me answer this!!!

Answers

Answer:

15 using the Pythagorean theorem.

hope it helps, plz mark me as brainliest.

Answer:

15 units is the answer.

Step-by-step explanation:

points are (-3,-4) and (6,8)

Pythagorean theorem can be written as,

[tex]d=\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2} \\\\d=\sqrt{(6-(-3))^2 + (8-(-4))^2}\\\\d=\sqrt{(9)^2+(12)^2} \\\\d=\sqrt{81+144} \\\\d=\sqrt{225} \\\\d=15[/tex]

∴ d = 15 units is the distance between the points.

Each month, 8 magazines arrive at Sydney's home. Write an equation that would show the number of motnths (n) it took for Sydney to receive 56 magazines.
btw this is multiple choice so this is the choices
A. 56n=8
B.n+8=56
C.8n=56
D.56-n=8
help me asap

Answers

C.
Since 8 magazines are areiving each month (n) and the total is 56, all you have to do is multiply 8 by n and you get 56, the actual answer would be 7 though.

Answer:

C.8n=56

Step-by-step explanation:

There are 24 students in Bianca’s GED class. 18 of the students passed the GED On their first try. Which percent of students passed the first time?

Answers

Answer:

75%

Step-by-step explanation:

18 divided by 24 equals .75 and that equals 75 as a percent.

if y + 3 = 14, what is the value of 3(y + 5)

Answers

Answer:

Step-by-step explanation:

y + 3 = 14

y = 11

3(y + 5) = 3(11 + 5) = 3(16) = 48

Answer: 48

Name the figure below in two different ways.

Answers

Answer:

MUV

VUM

Step-by-step explanation:

add the line arrow symbol

What value of x makes this equation true?
12x - 15 = 6 - 36

Answers

The answer is 3.75

12x - 15= 6-36
12x= 15+30
X=45/12
X=3.75

12(3.75) - 15 = 6-36
30=30

Answer:

i. The surface area of the ball is approximately 28.0 square inches.

ii. The volume of the ball is approximately 14.0 cubic inches.

Step-by-step explanation:

The ball has the shape of a sphere, so that;

C = 2[tex]\pi[/tex]r

9.4 = 2 x [tex]\frac{22}{7}[/tex] x r

65.8 = 44r

r = [tex]\frac{65.8}{44}[/tex]

r = 1.50 inches

The radius of the ball is 1.50 inches.

i. Surface area of a sphere = 4[tex]\pi[/tex][tex]r^{2}[/tex]

So that,

surface area of the ball = 4 x [tex]\frac{22}{7}[/tex] x [tex](1.5)^{2}[/tex]

= 28.2857

The surface area of the ball is approximately 28.0 square inches.

ii. Volume of the ball = Volume of a sphere = [tex]\frac{4}{3}[/tex][tex]\pi[/tex][tex]r^{3}[/tex]

Volume of the ball = [tex]\frac{4}{3}[/tex] x [tex]\frac{22}{7}[/tex] x [tex](1.5)^{3}[/tex]

= 14.1429

The volume of the ball is approximately 14.0 cubic inches.

Please help me
10 + 963 = ?

Answers

Answer:

Step-by-step explanation:

10+963=973

have a nice day

Answer:

10+963= 973

Step-by-step explanation: