What is the income distribution of super shoppers? A supermarket super shopper is defined as a shopper for whom at least 70% of the items purchased were on sale or purchased with a coupon. In the...

Use the table below to answer the questions.

(a) Compute the expected income ? of a super shopper. (Round your answer to two decimal places.)
? =  thousands of dollars


(b) Compute the standard deviation ? for the income of super shoppers. (Round your answer to two decimal places.)
? =  thousands of dollars

Extracted text: What is the income distribution of super shoppers? A supermarket super shopper is defined as a shopper for whom at least 70% of the items purchased were on sale or purchased with a coupon. In the following table, income units are in thousands of dollars, and each interval goes up to but does not include the given high value. The midpoints are given to the nearest thousand dollars. Income range 5-15 15-25 25-35 35-45 45-55 55 or more Midpoint x 10 20 30 40 50 60 Percent of super shoppers 20% 20% 15% 17% 18% 10%