"Lee Wants to Observe What People Do When They Visit

Multiple Choice

"Lee wants to observe what people do when they visit the gym. He visits every morning between 9 and 12 every day for two weeks. His coding schedule covers apparent age, and sex of the people being observed, plus a category for each piece of equipment they use." Why is his data likely to be biased?

A) Because he did not vary the times of his observation
B) Because he did not have mutually exclusive categories
C) Because he did not list all the equipment in the gym
D) Because he did not ask people for demographic information