Question

HELP

At a Junk Yard a study was conducted using 48 cars and found that the average mileage on a car before it was junked was 164,000 and the population standard deviation is known to be approximately 28,000. Construct a 99% confidence interval of what the actual average mileage is for a car before it is junked.

Answer 1

A 99% confidence interval of what the actual average mileage is for a car before it is junked is;  (153589, 174411)

How to find the confidence Interval?

The formula for confidence interval is;

CI = x' ± z(s/√n)

where;

x' is sample mean

s is standard deviation

n is sample size

z is critical value at confidence level

We are given;

x' = 164000

n = 48

s = 28000

CL = 99%

z-score at confidence level of 99% is 2.576

Thus;

CI = 164000 ± 2.576(28000/√48)

CI = 164000 ± 10410.78

CI = (164000 - 10410.78), (164000 + 10410.78)

CI = (153589, 174411)

Read more about Confidence Interval at; https://brainly.com/question/17097944

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