In order to set​ rates, an insurance company is trying to estimate the number of sick days that full time workers at an auto repair shop take per year. A previous study indicated that the population standard deviation is 2.8 days. How large a sample must be selected if the company wants to be​ 95% confident that the true mean differs from the sample mean by no more than 1​ day?
A. 512
B. 1024
C. 141
D. 31

Answers

Answer 1

Answer:

D. 31

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.

A previous study indicated that the population standard deviation is 2.8 days.

This means that [tex]\sigma = 2.8[/tex]

How large a sample must be selected if the company wants to be​ 95% confident that the true mean differs from the sample mean by no more than 1​ day?

This is n for which M = 1. So

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

[tex]1 = 1.96\frac{2.8}{\sqrt{n}}[/tex]

[tex]\sqrt{n} = 1.96*2.8[/tex]

[tex](\sqrt{n})^2 = (1.96*2.8)^2[/tex]

[tex]n = 30.12[/tex]

Rounding up, at least 31 people are needed, and the correct answer is given by option D.


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Answer:

(0,1) (1,-1/2), (2,-2)

Step-by-step explanation:

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Step-by-step explanation:

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a concert has 6 selections. there are 515 seats in each selection. about how many seats are in the concerts hall

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Answer:

3090

Step-by-step explanation:

6 x 515

Answer:

3090

Step-by-step explanation:

what is the common difference in the sequence (-3, 2, 7, 12, ...)

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Answer:

an=a1+d(n−1) a n = a 1 + d ( n - 1 )

Step-by-step explanation:

This is an arithmetic sequence since there is a common difference between each term. In this case, adding −5 to the previous term in the sequence gives the next term. In other words, an=a1+d(n−1) a n = a 1 + d ( n - 1 ) .

Solvex2
- 4x=21
using the zero product property.

Answers

Answer:

The answer is (x + 3) (x - 7) = 0

Step-by-step explanation:

x² - 4x = 21

x² - 4x - 21 = 0

x² - 7x + 3x - 21 = 0

x(x - 7) + 3(x - 7) = 0

(x + 3) (x - 7) = 0

Thus, The answer is (x + 3) (x - 7) = 0

-TheUnknownScientist

Use the completing the square method to transform the equation x^2 + 2x =13 into an equation of the form (x + a)^2 = b where a and b are real numbers. What are the values of a and b?

Answers

Answer: part A is 1 and part B is 14

Step-by-step explanation:

If the zeros of a parabola are at x = 4 and x = -2 what could be the equation of the parabola?

Answers

Answer:

the equation would be: y=(x-4)(x+2)

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Answers

Answer:

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Step-by-step explanation:

im not sure for the rest of it

C is the midpoint of AE. B is the midpoint of Ac. D is the midpoint of CE

Answers

Answer: d is correct

Step-by-step explanation:

Answer: what is the question

Step-by-step explanation:

PLEASE HELP ME!!!! I WILL MARK BRAINLIEST
find the length of the third side!
THANK YOU!

Answers

Answer:

The answer is 7

Step-by-step explanation:

[tex] {a}^{2} + {b}^{2} = {c}^{2} [/tex]

for our purposes we must rearrange this problem to find one of the sides, not the hypotenuse

[tex] {a}^{2} = {c}^{2} - {b}^{2} [/tex]

plugging in our numbers we get

[tex] {25}^{2} - {24}^{2} = 49[/tex]

[tex] \sqrt{49} = 7[/tex]

Assume y varies jointly with x and z. If y = 12 when x = 2 and z = 4, find x when y = 9 and z =6.

Answers

Answer:3

Step-by-step explanation:

help on this question ​

Answers

Answer:

sec t = 1/(cos t) = 1/(-3/4) = -4/3

How long would it take a cruise ship to travel 156 miles at an average speed of 26 mph

Answers

Answer:

The answer is 6 hours

Step-by-step explanation:

26x6=156

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B) 480.85

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Answers

Answer:

b

Step-by-step explanation:

Answer: D. Hope It helps!!!!!



In one game there are 85 spins.
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Answers

I dont know the question sory

Challenge A bag contains pennies, nickels, dimes, and quarters. There are 50 coins in all. Of the
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does the bag contain?
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Answers

The bag contains 28 dollars

83. A student estimated the height of a tree as 47
feet. If the actual height is 53 feet, what is the
percent error rounded to the nearest percent?
(Hint: Compare the estimated height to the actual
height.)
Poviow (SARZA
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Answers

I believe it’s 89%. I divided the estimated height by the actual height (47/53=0.8867) and then turned it into a percentage (0.8867=89%)

PLEASE HELP ME WITH THIS

Gabriela is solving the following equation. Her steps are shown:

Gabriella is not sure she has solved the problem correctly. How can you convince Gabriella if she has solved the problem correctly / incorrectly? If she has solved the problem incorrectly, solve it and convince her of the solution

Answers

Answer:

Solution given:

5(9x-8)=4(x+2)

45x-40=4x+8

45x-4x=40+8

41x=48

x=[tex] \frac{48}{41} [/tex]

Gabriella is not correct:

she has done in distribution

5(9x-8)=4(x+2)

45x-40=4x+8 not 45x-8=4x+2.

No, Gabriela is not solving correctly because her second step is wrong.

What is a fraction?

In a fraction the upper part is known as numerator and the lower part is known as denominator.

How to solve the problem?

The problem is as under

(9x-8)/4=(x+2)/5

The above problem is solved as

5(9x-8)=4(x+2)

45x-40=4x+2

41x=42

x=42/41

Hence the value of x is 42/41 therefore the solution of Gabriella is wrong.

Learn more about fraction at https://brainly.com/question/78672

#SPJ2

Five less then 3 times a number is 3 let x be unknown
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Answers

Answer:

3x-5=3

Step-by-step explanation:

Answer:

2.6 repeating Or 8/3(same thing in fraction form)

Step-by-step explanation:

So, lets iscolate the different parts of this euqation:

Five less than 3 times a number is 3

Or:

5 less than 3 * x = 3

This is a bit tricky here, but it should be:

(3*x)-5=3

Since order of operations, multipcation comes first.

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(3*x)-5=3

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Find the trig ratio. Reduce to
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6
А
8
[?]
sin A
US

Answers

Answer:

[tex]\frac{3}{5}[/tex]

Step-by-step explanation:

GIVEN :-

Measure of side opposite to ∠A (Perpendicular) = 6 unitsMeasure of side adjacent to ∠A (Base) = 8 units

TO FIND :-

sin A

FACTS TO KNOW BEFORE SOLVING :-

[tex]Hypotenuse = \sqrt{(Base)^2 + (Perpendicular)^2}[/tex][tex]\sin A = \frac{Side \: opposite \: to \: A}{Hypotenuse}[/tex]

PROCEDURE :-

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Side opposite to ∠A = Perpendicular of triangle =  6 units

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20 POINTS HELP FAST
Administrators surveyed students enrolled in a new school in order to choose the school mascot. There are 480 students enrolled in the school. What is the proportion needed to calculate the average number of students that chose the lion for the mascot?

Mascot Survey
Sample 1
Sample 2
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12
Ducks
8
Grizzlies
24
Grizzlies
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Lions
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Lions
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StartFraction 21 over 72 EndFraction = StartFraction x over 480 EndFraction
StartFraction 72 over 21 EndFraction = StartFraction x over 480 EndFraction
StartFraction 42 over 72 EndFraction = StartFraction x over 480 EndFraction
StartFraction 20 over 22 EndFraction = StartFraction x over 480 EndFraction

Answers

Answer:

its D.

Step-by-step explanation:

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Answer:

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0°F

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Answers

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Answer:

Sally is correct in claiming that [tex]\angle A[/tex] and [tex]\angle B[/tex] are supplementary.

Step-by-step explanation:

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Answers

Answer:

The perimeter is the length of the outline of a shape. To find the perimeter of a rectangle or square you have to add the lengths of all the four sides.

10 cm + 12 cm + 5 cm + 6 cm

= 33 cm


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Answers

Answer:

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Answers

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Answer:

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Step-by-step explanation:

y = a( x-h)^2 + k
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can somebody help me fill this out plz

Answers

Can you summarize this?

Find the x-intercepts of the parabola with
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Enter the correct answer.

Answers

the answer is x=-10 because i just did it and got 100

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Which document do you need to have on hand when preparing to file your tax return ?

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Answer:

a it's birth certificate

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