Battery life for a hand-held computer is normally distrituted and has a population standard deviation of 7 hours. Suppose you need to estimate a confidence interval estimate at the 95% level of confidence for the mean life of these batteries. Determine the sample size required to have a margin of error of 0.585 hours. Round up to the nearest whole number.

Answers

Answer 1

Answer:

A sample size of 551 is required.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

Population standard deviation of 7 hours.

This means that [tex]\sigma = 7[/tex]

Determine the sample size required to have a margin of error of 0.585 hours.

This is n for which M = 0.585. So

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]0.585 = 1.96\frac{7}{\sqrt{n}}[/tex]

[tex]0.585\sqrt{n} = 1.96*7[/tex]

[tex]\sqrt{n} = \frac{1.96*7}{0.585}[/tex]

[tex](\sqrt{n})^2 = (\frac{1.96*7}{0.585})^2[/tex]

[tex]n = 550.04[/tex]

Rounding up(as for a sample of 550 the margir of error will be a bit above the desired target):

A sample size of 551 is required.


Related Questions

Which input value produces the same output value for the two functions on the graph?

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Answer:

x=3

Step-by-step explanation:

Please make sure to add more information to the question next time. I had to do some research to find which question you are talking about. I hope this is one of the answer options because you didnt provide any of the answer options. Thanks :)

the intersection of the two lines of a function both equations have the same x and y

therefore,

x=3


The formula of calculating the gradient of a line is

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Answer:

To calculate the gradient of a straight line we choose two points on the line itself. From these two points we calculate: The difference in height (y co-ordinates) ÷ The difference in width (x co-ordinates). If the answer is a positive value then the line is uphill in direction.

Find the total surface area. Round to the nearest hundredth if necessary.

Answers

Answer:

166

Step-by-step explanation:

multiply the 6 by 2 and then multiply 13 by 10

to get 166

someone please help me answer this!!

Answers

Answer:

4 1/10

Step-by-step explanation:

4.1

= 4 + 1/10

= 4 1/10

Hope you understand!

Liam invests $5,000 in an account that pays 2.5% compound interest annually. He uses the expression P(1+r)t to find the total value of the account after t years. What will be the total value of the account after 3 years?

Answers

Answer:

The final balance is $5,389.

The total compound interest is $389.

Step-by-step explanation:

In a class of 50 students, 20 play hockey and 35 play football . 10 students play both hockey and football.​

Answers

You are missing the question

The vertices of ABC are A(-2,4), B (-2,2), and C (-5,2). If ABC is reflected across the line y=1 to produce the image A”B”C find the coordinates of the vertex B’

Answers

The vertices of ∆ABC are A (-2,5), B(-2,4), and C(-5, 3). If ∆ABC is reflected across the line y=-2 to produce the image ∆A’B’C, find the coordinates of the vertex A’ if ∆ABC is reflected across the line x= -2.

Help ASAP HELP ME PLEASE HELP

Answers

81+4x+5x+18=180
9x+99=180
9x=81
x=9
I hope I help you

Are these triangles congruent ?

Answers

Answer:no

Step-by-step explanation:

Nope, the corresponding angles are different degrees

State the name of the property illustrated. 5 + [7+(4)] = (5+7) + (4)

A. Communtative property of addition
B. Identity property of addiction
C. Associative property of addition

Answers

The answer is C. Associative property of addition

Can someone help me with 1 2 and 3 please

Answers

Answer:

1. vertical angles

2. 90°, complementary

3. 180°, supplementary

Answer:

1) Vertical angles

2) 90°, complementary

3) 180°, supplementary

Step-by-step explanation:

1) Intersecting lines form vertical angles.

According to the word problem, ∠APC and ∠DQB are formed by intersecting lines, meaning they are vertical angles.

2) ∠AQV is 30°, and ∠VQT is 60°.

30° + 60° = 90°. The sum of these angles is 90°.

And, complementary angles are two angles with measures that sum up to 90°.

3) ∠AQC is 150°, because 30° + 60° + 60° = 150°.

∠CQB is 30°.

And, 150° + 30° = 180°.

Supplementary angles are two angles with measures that sum up to 180°.

What is the median value of the data set shown on the line plot?
Enter your answer in the box.
Help

Answers

Answer: 30

Step-by-step explanation:

You put the numbers from least to greatest. 27,28,28,29,29,29,30,30,30,31,31,31,33,34. Then the median would be 30 and 30. So then you would add the two numbers 30 + 30 then divide by 2. 60/2 and the answer would be 30. Hopefully that was helpful.

what equation represents a line that when if graphed, passes through the points (0, -1) and
(1, 1).

Answers

Y= 2x-1
Explanation: First, you find slope. If the first point it x-axis point is 0 and the second x-axis point is 1 then you already know the answer is over 1, so you have to figure out how many up you are going on the y-axis from -1 to 1. Which is 2, so your slope is 2/1 or just 2. Next, you find your y-intercept, which is where the line crosses the y-axis, and the easy way to find this is finding what y is equal to when x is equal to 0, in the problem you are told (0, -1) as a point, so they gave you your y-intercept right there, which is -1. Finally you right the equation in slip intercept form (y= mx+b) which is y= 2x-1

25, 87, 90, 25, 67
Mean:
Median:
Mode:
Range:

500,100,300,300,500,100

Mean:
Median:
Mode:
Range:

5,5,4,4,3,3,2

Mean:
Median:
Mode:
Range:

Answers

Answer:

mean number 1 25+87+90+25+67=294 294/5 58.8 question 2 500+100+300+300+500+100=1800 1800/6 =300

Answer:

Step-by-step explanation:

Mean: 289 (not sure)

Median: 90

Mode: 25

Range: 65

Mean: 1794 (still not sure)

Median: 300

Mode: 400?

Range: 400

Mean: 19

Median: 4

Mode: i dont know

Range: 3

Edwin is making brownies. He has m cups of flour. He realized that he needs 3/4 more flour than he currently has to make the brownies. Which expression represents the total amount of flour he needs to make the brownies? ​

Answers

Answer:

3/4 + m

Step-by-step explanation:

Answer:

3/4 + m

Step-by-step explanation:

63°
13°
Choose the equation that best describes the image.

Answers

Answer:

13+63 if I'm not wrong......

Which of these groups of relative frequencies would be best represented by a
pie chart?
A. 16%; 18%; 17%; 16%; 17%; 16%
B. 20%; 19%; 21%; 20%; 20%
C. 6%; 14%; 80%
D. 25%; 24%; 26%: 25%

Answers

Answer:

C

Step-by-step explanation:

different size wedges would be the most visibly different

c is the answer hope this helps

Which function describes this table of values
Is it A or B or C or D

Answers

Answer:

c

Step-by-step explanation:

In the formula, l = a + (n - 1)d make d as the subject. Find d when l = 10, a = 2, n = 5.

Answers

Answer:

d=2

Step-by-step explanation:

l=a+(n-1) d

10=2+(5-1)d

10-2=4d

8=4d

d=2...

Answer:

2

Step-by-step explanation:

I = a + (n - 1)d

10 = 2 + (5 - 1)d

10 = 2 + 4d

10 - 2 = 4d

8 = 4d

d = 2

Manny goes bowling.

- He has $25.00 to spend.

- He spends $4.25 to rent shoes.

- He spends $2.50 for each game he bowls.

Which inequality can Manny use to determine x, the greatest number of games he can bowl?

A. 2.5+4.25x≥25

B.4.25+2.5x≥25

C. 2.5+4.25x≤25

D. 4.25+2.5x≤25

Answers

Answer:

D

Step-by-step explanation:

D is the answer because spend satisfied value not more than 25

Which value is equivalent to V-25?
A. -5i
B. -5
C. 5
OD. 5i​

Answers

Answer:

[tex]\sqrt{-25} = 5i[/tex]

Step-by-step explanation:

Given

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

Required

An equivalent

We have:

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

Express -25 as -1 * 25

[tex]\sqrt{-25} = \sqrt{-1 * 25}[/tex]

Split

[tex]\sqrt{-25} = \sqrt{-1} * \sqrt{25}[/tex]

[tex]\sqrt{25} = 5[/tex], so:

[tex]\sqrt{-25} = \sqrt{-1} * 5[/tex]

[tex]\sqrt{-1} = i[/tex] --- complex numbers

So:

[tex]\sqrt{-25} = i * 5[/tex]

[tex]\sqrt{-25} = 5i[/tex]

Hence, the equivalent is (D)

What is the slope of the line perpendicular to 2x-3y=8

Answers

Answer:

y = - [tex]\frac{3}{2}[/tex]x - [tex]\frac{8}{3}[/tex]

Step-by-step explanation:

2x-3y=8

rewrite, solve for y

3y = 2x - 8

divide by 3

y = [tex]\frac{2}{3}[/tex]x - [tex]\frac{8}{3}[/tex]

perpendicular = negative reciprocal slope = - [tex]\frac{3}{2}[/tex]

10 x __= 5/6 + 5/6 Solve.

Answers

Answer:

[tex]let \: that \: number \: be \: m \\ 10 \times m = \frac{5}{6} + \frac{5}{6} \\ 10m = \frac{10}{6} \\ m = \frac{10}{60} \\ m = \frac{1}{6} [/tex]

Find the critical value t for the confidence level c= 0.98 and sample size n=7.
Click the icon to view the t-distribution table.
=(Round to the nearest thousandth as needed.)

Answers

Answer:

The critical value is T = 3.143.

Step-by-step explanation:

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 = 7 - 1 = 6

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 6 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 3.143.

The critical value is T = 3.143.

If the figure is reflected over the x-axis, what are the coordinates of point R?

Answers

Answer:

R' (3,-3)

Step-by-step explanation:

25 points!!!

A system of equations is shown.
2x + 2y = 24
X = 3y

What is the value of x + y?

Enter your response here: Only 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -, -, and / are allowed in your answer.
Answers that are mixed numbers must be entered as an improper fraction or a decimal.​

Answers

Answer:

x+y=12

Step-by-step explanation:

First, substitute 3y for the spots with x:

2(3y) + 2y = 24

6y+ 2y = 24

8y= 24

y= 3

Then sub in 3 in the y place:

x= 3(3)

x= 9

Then plug in the x and y values in the equation:

9 + 3 =12

Good Luck!!!

plz mark me Brainliest!

If you know this you’re very smart!

Answers

Answer:

Its B and its not that hard because im doing that rn lol but do you need me to explain?

Step-by-step explanation:

How to convert kilometres to minutes

Answers

Here you go I took from video but its really easy way to solve this problem

A pole that is 2.5 m tall casts a shadow that is 1.07 m long. At the same time, a nearby tower casts a shadow that is
37.25 m long. How tall is the tower? Round your answer to the nearest meter.

Answers

Answer:

The tower is 61.65 meters tall.

Step-by-step explanation:

Kenzie finds purple, blue, and silver space rocks while exploring, 2/3 of the rocks are purple and 3/4 of the remainder are blue. If there are 3 silver rocks, how many space rocks does Kenzie have?a

Answers

Answer:

There were 36 space rocks in total.

Step-by-step explanation:

First, you need to find what fraction of the original rocks are silver.

If 2/3 are purple, then 1/3 of them are not.

If 3/4 of the remaining 1/3 are blue, then 3/4 x 1/3 = 3/12 rocks are blue.

2/3 of the rock are purple, 3/12 of them are blue, and the remaining is silver.

So, you need to do 2/3 - 3/12, then find common denominators so, 8/12 - 3/12 which = 1/12.

This means 1/12 of the rocks are silver. If there are silver rocks, you need to find a suitable equation that needs to be solved.

So:

1/12r = 3

r = 36 silver rocks

There were 36 space rocks in total.

hope this helps :)

Ídek I wish I can help you sorry
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