“Have you ever seen anything that you believe was a spacecraft from another planet?” This was the question put to 1,500 American adults in a national poll conducted by ABC News and The Washington Post. The pollsters used random-digit telephone dialing to contact adult Americans until 1,500 responded. Ten percent (i.e., 150) of the respondents answered that they had, in fact, seen an alien spacecraft. (Chance, Summer 1997) No information was provided on how many adults were called and, for one reason or another, did not answer the question.
a. Identify the data collection method.
b. Identify the target population.
c. Comment on the validity of the survey results.