In a random sample of 50 ?refrigerators, the mean repair cost was ?$146.00 and the population standard deviation is ?$17.80.
Construct a 90?% confidence interval for the population mean repair cost. Interpret the results.
Construct a 90% confidence interval for the population mean repair cost.
The 90?% confidence interval is ( ? , ? ).
?(Round to two decimal places as? needed.)
Interpret you results. Choose the correct answer below.
A.With 90?% ?confidence, it can be said that the confidence interval contains the true mean repair cost.
B.With 90?% ?confidence, it can be said that the confidence interval contains the sample mean repair cost.
C.The confidence interval contains 90% of the mean repair costs.