1. How can a RANDOM sample be selected?

There are lots of ways ranging from picking names out of a hat to using computers.

On a computer, most spreadsheets have a RAND(..) function and most calculators have a RND# button.

2. What is the difference between a sample and a population?

population covers all of the group being studied.

sample is part of that group.

The larger the sample, the more likely the sample is to be representative to a population.

3. Why should a sample be random ?

If a sample is not RANDOM it is likely to lead to BIASED results.