A retail business is interested in estimating the average amount its credit card customers spend on their rst visit to their new store. Eighteen credit card accounts were randomly sampled with the following results: mean = $60.1 and standard deviation = $17.8. Calculate a 99% condence interval for the average amount its credit card customers spent on their first visit to the new store, assuming that the amount spent follows a normal distribution. Answer: $60.1 1-:l (please provide a positive number to 2 decimal places). Check