Samples from specific situations are not likely to create representative random samples.
Call one number from each page of an online phone listing for your town between noon and
Not likely; this samples the population of people with phone numbers listed online that are home midday.
Also, we only get responses from those who agree to participate.
Survey each person leaving a local grocery store.
Survey each person leaving a local movie theater.
Walk around downtown and survey every fourth person you see.
Could you make a representative sample by surveying a few people from each of the situations described in parts (a) through (d) above? Explain, and consider what problems might still remain.