Indicate whether each statement below is true or false.

If false, explain why.

a) Asking viewers to call into a 900 number (for which there is a toll charge) is a good way to produce a representative sample.

b) When writing a survey, it’s a good idea to include as many questions as possible to ensure efficiency and to lower costs.

c) A recent poll on a website was valid because the sample size was over 1,000,000 respondents.

d) Malls are not necessarily good places to conduct surveys because people who frequent malls may not be representative of the population at large.