A survey of 50 retail stores revealed that the average price of a microwave was $375 with a standard error of $20. If 90% and 95% confidence intervals were developed to estimate the true cost of the microwave, what similarities would they have?
A) Point estimates
B) Z-variates
C) Standard errors
D) Both "a" and "c"

Question

Quizplus · Accepted Answer

Both confidence intervals would have the same point estimate (average price of $375) and the same standard error of $20. The only difference between the two intervals would be the critical value used based on the desired level of confidence. Therefore, choices "a" and "c" are correct. The use of z-variates is implied since the sample size is greater than 30, and the population standard deviation is unknown.

A Survey of 50 Retail Stores Revealed That the Average