To attract business, a clothing store mails discount coupons to residents of a town. To estimate the proportion of the store's shoppers who are using the coupons, the store manager selects a random sample of 100 customers
who visit the store on a weekend. The manager finds that 38 of them are using the coupons mailed to their homes.
Which of the following describes the sample in this setting?
all residents of the town
the 38 shoppers who used coupons
the 100 randomly selected shoppers
all shoppers in the store on the weekend