In a random sample of 55 refrigerators, the mean repair cost was $119,00 and the

Question

In a random sample of 55 refrigerators, the mean repair cost was $119,00 and the population standard deviation is $16, 70. Construct a 95% confidence interval for the population mean repair cost. Interpret the results. Construct a 95% confidence interval for the population mean repair cost. The 95% confidence interval is(). Interpret you results. Choose the correct answer below. A. With 95% confidence, it can be said that the confidence interval contains the true mean repair cost. B. The confidence interval contains 95% of the mean repair costs. C. With 95% confidence, it can be said that the confidence interval contains the sample mean repair cost.

Explanation / Answer

Mean repair cost = 119
Stdev = 16.7
n=55

The 95% interval is given by formula
=Xbar +/- Z*Stdev/sqrt(n)
=119+/-1.96*16.7/sqrt(55)
=114.59 to 123.41

Remember the Confidence interval is about the population parameter
- Hence, C is eliminated
B is not the right way to interpretation
A is the right answer

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