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nasty-shy [4]
3 years ago
12

A​ car-rental company is interested in the amount of time its vehicles are out of operation for repair work. State all assumptio

ns and find a 90​% confidence interval for the mean number of days in a year that all vehicles in the​ company's fleet are out of operation if a random sample of 10 cars showed the following number of days that each had been inoperative. 10 13 20 15 17 22 8 14 19 7 State all assumptions. Select all the assumptions below. A. The sample comes from a normal population B. The sample size is at least 30 C. It is a random sample D. The variance is less than the mean Find a 90​% confidence interval for the population mean. The 90​% confidence interval is from a lower limit of nothing to an upper limit of nothing. ​(Round to two decimal places as​ needed.)

Mathematics
1 answer:
AlladinOne [14]3 years ago
6 0

Answer:

13.57 < µ < 15.43

Step-by-step explanation:

Assume:  We have to assume the sample comes from a normally distributed population because we do not know the population standard deviation.  

We assume that it was a random sample.

Do not assume:  The sample size is at least 30 because we are that it's 10.  Don't assume the variance is less than the mean because we can calculate it and will know for sure.

To find a 90% confidence interval we need to find the sample mean and sample standard deviation.  See attached photo 1 for the calculations

See attached photo 2 for the construction of the confidence interval

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N76 [4]

Answer:

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Step-by-step explanation:

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8 0
2 years ago
A teenager who is 5 feet tall throws an object into the air. The quadratic function LaTeX: f\left(x\right)=-16x^2+64x+5f ( x ) =
tia_tia [17]

Answer:

At approximately x = 0.08 and x = 3.92.

Step-by-step explanation:

The height of the ball is modeled by the function:

f(x)=-16x^2+64x+5

Where f(x) is the height after x seconds.

We want to determine the time(s) when the ball is 10 feet in the air.

Therefore, we will set the function equal to 10 and solve for x:

10=-16x^2+64x+5

Subtracting 10 from both sides:

-16x^2+64x-5=0

For simplicity, divide both sides by -1:

16x^2-64x+5=0

We will use the quadratic formula. In this case a = 16, b = -64, and c = 5. Therefore:

\displaystyle x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

Substitute:

\displaystyle x=\frac{-(-64)\pm\sqrt{(-64)^2-4(16)(5)}}{2(16)}

Evaluate:

\displaystyle x=\frac{64\pm\sqrt{3776}}{32}

Simplify the square root:

\sqrt{3776}=\sqrt{64\cdot 59}=8\sqrt{59}

Therefore:

\displaystyle x=\frac{64\pm8\sqrt{59}}{32}

Simplify:

\displaystyle x=\frac{8\pm\sqrt{59}}{4}

Approximate:

\displaystyle x=\frac{8+\sqrt{59}}{4}\approx 3.92\text{ and } x=\frac{8-\sqrt{59}}{4}\approx0.08

Therefore, the ball will reach a height of 10 feet at approximately x = 0.08 and x = 3.92.

7 0
2 years ago
Toni simplified the expression , 22 × (16 −32 +1) ÷ 8. For Toni's first and second steps, he simplified the expression inside th
Anna007 [38]
When you subtract and add what is in the parentheses you would get -15 so I’m guessing he didn’t go from left to right when working inside the parentheses but when you solve the whole problem out you would get the answer: -41.25 If I missed something or you need me to show the work just let me know but I hope this helps !
6 0
3 years ago
Doesn't it say Odd integers, I'm quite confused.
dem82 [27]
What says odd integers???
4 0
3 years ago
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Ms. B drives a maximum of 10 miles per week. If she drives 5 days per week, how much per day?
DanielleElmas [232]

Answer:

2 miles about

Step-by-step explanation:

10 miles max divided by 5 days is two miles per day

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3 years ago
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