A Major Department Store Chain Is Interested in Estimating the Average

Multiple Choice

A major department store chain is interested in estimating the average amount its credit card customers spent. Fifteen credit card accounts were randomly sampled and analyzed with the following results: = $50.50 and = 400. Assuming the distribution of the amount spent is approximately normal, what is the shape of the sampling distribution of the sample mean that will be used to create the desired confidence interval for ?

A) approximately normal with a mean of $50.50
B) a standard normal distribution
C) a t distribution with 15 degrees of freedom
D) a t distribution with 14 degrees of freedom