A pharmacy wants to survey its customers to find out which brand of toothpaste they prefer.

Which survey methods are likely to be biased?

Select each correct answer.

Those customers who buy toothpaste with a coupon are selected, and the toothpaste brand they purchased is recorded.

A survey is sent to the customers who are on the pharmacy’s frequent buyer list.

Every 10th customer who enters the pharmacy on 1 day is selected and asked.

One hundred people from the pharmacy’s customer list are selected at random, called on the phone, and asked.