A university surveyed recent graduates of the English department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000. The population standard deviation is $2,500. A 95% confidence interval is constructed. What does the confidence interval mean?
A)The population mean is in the interval.
B)The population mean is not in the interval.
C)The likelihood that any confidence interval based on a sample of 400 graduates will contain the population mean is 0.95.
D)There is a 5% chance that the computed interval does not contain the population mean.

Question

Quizplus · Accepted Answer

DThe confidence interval means that if we were to take many samples and construct a confidence interval from each, 95% of those intervals would contain the true population mean. This is reflected in choice C. Choice D is another way of stating the concept, emphasizing the complement of the confidence level (100% - 95% = 5%), indicating there's a 5% chance that a given interval does not contain the population mean.

A University Surveyed Recent Graduates of the English Department for Their