The nexttwoquestions (17and18) refer to the following:

The amountXspent (in $) by customers in the grocery store express lane follows some

right-skewed distribution with mean $24 and standard deviation $15.

17. What is the probability that the average amount spent by the next three customers is more than $20?

(A) 0.4619

(B) 0.6772

(C) 0.8186

(D) 0.7673

(E) impossible to calculate with the information given

1. What is the approximate probability that the next 40 customers spend less than $1,000 in total?
2. (A) 0.5199 (B) 0.6064 (C) 0.6628 (D) 0.5784 (E) 0.6331
3. An economist calculates that, in order to estimate the true mean amount spent per year by Canadians on Christmas presents to within $60 with 95% confidence, she requires a sample of 90 Canadians. What sample size would be required to estimate the true mean amount spent per year by Canadians on Christmas presents to within $20 with 95% confidence?
4. (A) 10 (B) 30 (C) 156 (D) 270 (E) 810