2.39 A Hong Kong snack-food vendor offers 3 types of boxed “lunches to go,” priced at $3, $5, and $10, respectively.

The vendor would like to establish whether there is a relationship between the price of the boxed lunch and the number of sales achieved per hour.

Consequently, over a 15-day period the vendor records the number of sales made for each of the 3 types of boxed lunches. The following data show the boxedlunch price (x) and the number sold (y) during each of the 15 lunch hours.

(3 , 7), (5 , 5), (10, 2), (3 , 9), (5 , 6), (10, 5), (3 , 6), (5 , 6),

(10, 1), (3 , 10), (5 , 7), (10, 4), (3 , 5), (5 , 6), (10, 4)

a. Describe the data numerically with their covariance and correlation.

b. Discuss the relationship between the price and number of boxed lunches sold.