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

Does the point (-8, 8) satisfy the inequality 16x + 15y = -8?
yes
no

Answers

Answer:

Yes

Step-by-step explanation:

16x+15y=-8

16(-8)+15(8)=-8

-8=-8

Hope that helps :)

Answer:

True

Step-by-step explanation:

The left side  − 8  is equal to the right side  − 8 , which means that the given statement is always true.

Solve the equation by completing the square. Round your solutions to the nearest hundredth if necessary. x^2+2x=5

Answers

Answer: The correct answers are -3.45 and 1.45

Step-by-step explanation: The only problem you had was you rounded it to the tenths place instead of the hundredths place.

Sorry for getting back to you late.


Please help really quick

Answers

Answer:

88 yd.²

Hope this helps!

Answer:

Area= 88 sq. yd.

Step-by-step explanation:

The formula for the area of a triangle is A= h b/2.

This means you just divide 16 (the base) by 2 to get 8, and then multiply it by 11 (the height). This gives you 88

There are 5 slices in the pizza. Wayne ate 2 slices of the pizza. What fraction of the pizza is left?

Answers

Answer:

3/5

Step-by-step explanation:

5/5 - 2/5 = 3/5

Answer: 3/5

If they are 5 and 2 were eaten, there are 3 left. You would put the amount left as the numerator over the denominator of total slices there were from the start. You cant simplify 3/5 down so it stays that way.

A cuboid with a volume of 924 cm' has dimensions
4 cm, (x + 1) cm and (x + 11) cm.
Show clearly that x2 + 12x – 220 = 0
Solve the equation by factorisation, making sure you show the factorisation.
State both values of x on the same line.
Finally, find the dimensions of the cuboid, writing all three on one line.

Answers

Answer:

4cm, 11cm, 21cm

Step-by-step explanation:

4(x + 1)(x + 11)

4(x ^ 2 + 12x + 44)

x ^ 2 + 12x + 11 = 231

x ^ 2 + 12x + 11 - 231 = 0

x ^ 2 + 12x - 220 = 0

(x - 10)(x + 22) = 0

x = 10 and x = - 22

4cm , 11cm , 21cm

Hope it helps you xx

Answer:

Dimensions = 4cm, 11cm and 21 cm.

Step-by-step explanation:

x2 + 12x - 220 = 0

x2 + 22x - 10x - 220

= x(x+22) -10(x+22)

=(x+22)(x-10)

x + 22= 0

-22       -22

x = -22 (x cant be negative so this is wrong)

x-10 = 0

+10      +10

x = 10 (positive so its correct)

4 , (10+1), (10+11)

= 4, 11, 21 cm.

On a certain hot summer's day, 321 people used the public swimming pool. The daily prices are $1.75 for children and $2.00 for adults. The receipts for admission totaled $634.25. How many children and how many adults swam at the public pool that day?​

Answers

Answer:

31 children and 290 adults

Step-by-step explanation:

Let a = number of adults and c = number of children.

a + c = 321

2a + 1.75c = 634.25

Multiply both sides of the the first equation by -2 and add it to the second equation.

         -2a -     2c = -642

(+)       2a + 1.75c = 634.25

--------------------------------------

                 -0.25c = -7.75

Divide both sides by -0.25

c = 31

Use the first equation to find a.

a + c = 321

Substitute 31 for c.

a + 31 = 321

Subtract 31 from both sides.

a = 290

Answer: 31 children and 290 adults

120 children and 388 adults bought tickets for the swimming pool
Explanation:
Create two simultanous equations:
Let c stand for the number of children that bought a ticket, and a stand for the number of adults that bought a ticket, you get your first equation, being
c
+
a
=
508
then, you now create a second equation for the prices of the tickets.
(price of childrens tickets)(number of children that swam)+(price of adults tickets)(number of adults that swam) = total money collected
so:
1.75
c
+
2.25
a
=
1083.00

now we still know, that
a
=
508

c

so we can substitute it into the second formula
1.75
c
+
2.25
(
508

c
)
=
1083

now its just simple algebra
1.75
c
+
1143

2.25
c
=
1083

60
=
0.5
c
so:
c
=
120
now we know, that 120 children went to the swimming pool.
and we still have the formula from before:
a
=
508

c
so
a
=
388

PLEASE HELP!!!!!!!!!!!!!!!!!!!!!1111 I REALLY NEED HELP I A, BEGGIN YOU GUYS!!!!!!!!!!!!!!!!!!!!!!!!!!! ILL GIVE BRAINLIEST AND EXTRA POINTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answers

Answer:

Equivalent: 6(y - 3) AND 2(3y - 9)

Not Equivalent: 3(y - 6) AND 2(y - 9)

Step-by-step explanation:

4y - 2(5 - y + 4)

4y - 2(9 - y)

4y - 18 + 2y

6y - 18 (Everything must be equivalent to this)

3(y - 6) NOT EQUIVALENT

3y - 18

6(y - 3) EQUIVALENT

6y - 18

2(y - 9) NOT EQUIVALENT

2y - 18

2(3y - 9) EQUIVALENT

6y - 18

A chocolate shop sells chocolates with a variety of different fillings.

hazelnut 68
caramel 8
orange 8

What is the probability that a randomly selected chocolate will have caramel filling?

Write your answer as a fraction or whole number.

Answers

Answer:

There is a [tex]\frac{2}{21}[/tex] chance of picking caramel-filled chocolate.

Step-by-step explanation:

To set this up, you need to make it a fraction. The denominator of the fraction is how many total chocolates you can pick from. You can figure this out by adding all of the chocolate choices together:

68 hazelnut + 8 caramel + 8 orange = 84 chocolates.

The numerator is defined by the number of caramel chocolates, in this case it is 8. That means the fraction will look like:

[tex]\frac{8}{84}[/tex]

Now that can be simplified down. I divided the top and bottom both by 4 to get  [tex]\frac{2}{21}[/tex] and that is as far down as it can go. Therefore that is the probability you will get a caramel-filled chocolate.

On the midnight shift, the number of patients with head trauma in an emergency room has the probability distribution shown below. x 0 1 2 3 4 5 Total P(x) .02 .31 .25 .19 .13 .10 1.00 (a) Calculate the mean and standard deviation. (Round your mean value to 2 decimal places and standard deviation to 3 decimal places.) Mean Standard deviation (b) Describe the shape of this distribution. multiple choice Skewed to the right Skewed to the left Symmetric

Answers

Answer:

Mean = 2.40

Standard deviation = 1.356

Step-by-step explanation:

Given the data:

X :___ 0 __1 ___ 2 ___ 3 __ 4 __ 5 __Total

P(x)_0.02_0.31_0.25_0.19_0.13 _0.10_ 1.00

The mean [E(X)]

Σx*p(x)

(0*0.02)+(1*0.31)+(2*0.25)+(3*0.19)+(4*0.13)+(5*0.10) = 2.4

The standard deviation :

Std(x) = sqrt[VAR(x)]

Var(x) = ((0^2 * 0.02)+(1^2 * 0.31)+(2^2 * 0.25)+(3^2 * 0.19)+(4^2 * 0.13)+(5^2 * 0.10)) - 2.4^2

Var(X) = 7.6 - 5.76 = 1.84

Std(X) = sqrt(1.84) = 1.356 (3 decimal places)

CONVERT THE PERCENTAGES FRACTION 120%​

Answers

Answer:

[tex]\frac{6}{5}[/tex]

Step-by-step explanation:

Answer:

6/5

Step-by-step explanation:

Its 6/5..

1 = 20%

Please give brainliest

Please help !!!!!!!!!!!!!

Answers

Answer:

1) x= sqrt 98 = 7 sqrt 2

Step-by-step explanation:

Find the Mode:
88, 82, 81, 89, 77, 95
89, 90, 81, 75

Answers

Answer:

81 is the mode

Step-by-step explanation:

THe mode is the number ina. Set of data that appears the most. In this case, 81 appears twice while all the other numbers only appeared once. So 81 in this case is the mode.  

Yukarıda verilen şekilde,
[LK // [NP, m(LMN) = 40°, m(KLM) = aº,
m(MNP) = bº ve b = a + 70°'dir.
Buna göre a kaç derecedir?
A) 30
B) 35
C) 60
D) 75

Answers

C, 60 hope this helps it helped me on my test

Help plssssssssss I don’t wanna fail

Answers

Answer: 5:15 PM

Step-by-step explanation: All you need to do is add numbers together. Make sure to remember that there is 60 minutes in one hour :)

Silvia randomly picked 12 flowers from a garden. Three of the flowers she picked were roses. What is the experimental probability that the next flower she picks will be a rose? ________

Answers

Answer:

1/4

Step-by-step explanation:

I could be wrong but that's what I would put

Answer:

P(next to be rose) = 1/4

Explanation:

in general when she picked 12 flowers, 3 were roses

3/12 = 1/4

In a certain school, there are 4 girls for every 5 boys. If there are 560 girls in the school, how many boys attend school?​

Answers

Answer:

700

Step-by-step explanation:

4girls=5boys

560girls=?

560*5/4

=700boys

Pls help me complete this

Answers

Answer:

wow thats alot of "stuff"

Step-by-step explanation:

Answer:

For the first, top one, it is Outcome

For the second one, it is Event

For the third one, it is Trial

For the fourth one, it is Experimental Probability

For the fifth one, it is Probability

A game-show spinner has these odds of stopping on particular dollar values: 40% for $5, 25% for $100, 20% for $500, and 15% for $1000. What are the odds of a player winning $5 or $100?

Answers

Answer:

13÷ 23

Step-by-step explanation:

The computation of the odds of player winning is shown below;

For $5 it is 40%

And, for $100 it is 25%

so for total it is

= 40% + 25%

= 65%

And, the total percentage is 100%

So, the odds in favor is

65:100

13:20

Now for winning it would be 13÷ 23

o que significa 1E+76 ?????

Answers

Answer:

e means error at least when the number is higher than the computor can calculate or it is just a variable

Step-by-step explanation:

Anna bought textbooks and notebooks at the bookstore. The number of notebooks she bought was four
more than the number of textbooks. If the total number of notebooks she bought was 7, how many
textbooks were bought?

Answers

Answer:

3 textbooks

Step-by-step explanation:

Well 7 notebooks were brought.

She brought 4 more notebooks then textbooks.

7-4=3

Answer:

If Anna bought seven notebooks and the number of notebooks she bought was four more than textbooks, all you have to do it subtract four from seven to get three.

Step-by-step explanation:

7 - 4 = 3

yes
i will help you if you want is that ok

Answers

Answer:

ok

Step-by-step explanation:

Answer:

okay

Step-by-step explanation:

okay i will accept your help

Help pls i'm lost i really need help

Answers

-17, +20, -5, +14, 100, -17, +10, -9, -8, +11

Which of these graphs represents a function ?

Answers

Answer:

Graph C

Step-by-step explanation:

I’ll mark as BRANLIEST!!

35 POINTS!!

- Determine whether each table or rule represents a linear or exponential function. Explain why or why not.

Answers

1 is exponential because the numbers, when multiplied together, do not make the same numbers

2 is exponential because of an exponent being the modified variable

3 is linear because it is just multiplication which is a simple pattern

Answer:

Definitions of gravitational force. (physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface. synonyms: gravitation, gravitational attraction, gravity.

Betty has $40 in her pocket. She brought 12 identical bags of popcorn. Betty was left with $10 after buying the popcorn. What was the price, in dollars, of each bag of popcorn?
(a) 0.55
(b) 2.50
(c) 4.17
(d) 5.20

Answers

Answer:

2.50 (b)

Step-by-step explanation:

30 divided by 12 is 2.5 which is equal to 2.50 :)

Answer:

b) 2.50

Step-by-step explanation:

$40 - $10 = $30 spent on popcorn

$30/12 = $2.50 per bag

The formula for the volume of a cone is V =
3
bah
Solve V =
on for b, the base of the cone.

Answers

Answer:

oh thats easy thats 7

Step-by-step explanation:

i guess

HELPP QUICKK PLEASSEEE​

Answers

Answer:

Questions are blur can you post a much clearer one?

Can somebody solve this?

Answers

Answer:4

Step-by-step explanation:2+2=4

10x+2
To find the perimeter, you would add all of the sides up.
3x+2+3x+2+2x-1+2x-1
=10x+2

I need the answer, help me please

Answers

Perpendicular = opposite sign and reciprocal slope
Y = 3/2x + 1
The slope is 3/2, opposite sign = -3/2 now reciprocal = -2/3
Y = -2/3x + b
Plug in the point (6,-2)
-2 = -2/3(6) + b
-2 = -12/3 + b
-2 = -4 + b, b =2
Solution: y = -2/3x + 2
X=-0.6 or -2/3

Substitute y for 0

multiply both sides of the equation by 2
Move the variable to the left-hand side and change its sign

Divide both sides of the equation by -3

The life of light bulbs is distributed normally. The standard deviation of the lifetime is 15 hours and the mean lifetime of a bulb is 590 hours. Find the probability of a bulb lasting for at most 605 hours. Round your answer to four decimal places.

Answers

Answer:

0.8413 = 84.13% probability of a bulb lasting for at most 605 hours.

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.

The standard deviation of the lifetime is 15 hours and the mean lifetime of a bulb is 590 hours.

This means that [tex]\sigma = 15, \mu = 590[/tex]

Find the probability of a bulb lasting for at most 605 hours.

This is the pvalue of Z when X = 605. So

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

[tex]Z = \frac{605 - 590}{15}[/tex]

[tex]Z = 1[/tex]

[tex]Z = 1[/tex] has a pvalue of 0.8413

0.8413 = 84.13% probability of a bulb lasting for at most 605 hours.

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