One question in a survey about what kind of cars people prefer to drive is:

"Would you prefer a 'soccer Mom' minivan or a 'cool Mom' convertible?"

This question contains:

A) data

B) statistics

C) bias

D) errors

Answer: C) bias

The question is biased toward mothers, and does not consider women who do not have kids. A biased question leans toward a certain group, or set of groups, of people; at the same time, other groups are left out and not represented. One way to remove the bias is to ask "Would you prefer a minivan or a convertible?".