Statistical Reasoning Suppose there are 200 teachers at CHS, Mrs. King wants to perform a survey to find information about teachers' opinions of teaching 5 out of 6 periods. She comes to AP Statistics for help.

a) Explain how to select 20 teachers using an Simple Random Sample. Give a step-by-step account.

b) Explain how to select 20 teachers using a stratified random sample.

c) Explain how to use a systematic random sample to select the 20 teachers.

d) She decides to stop the first 20 teachers that she sees in the foyer. Explain why this would not be a good idea.