Select the true statement(s) about studies and random samples. A. A simple random sample is representative of the entire population of interest.

B. In an observational study, the researchers record the response for a specific variable for each individual or object.

C. The number of simple random samples is always infinite.

D. In an experimental study, the researchers investigate the effects of certain conditions on at least three different groups.

E. A simple random sample is a systematic pattern for selecting objects from a population.