Indicate whether each statement below is true or false. If false, explain why. a) Asking viewers to call into an 800 number is a good way to obtain 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.

a. False

b. False

c. False

d. True

Explanation:

Statement A is false because a representative sample can be obtained by asking viewers who call into an 800 number. The sample is formed from their voluntary response and would likely be biased. Among the population, there would be a strong opinion due to the type of invitation given. Thus, it could not be a representativeof the population.

Statement B is false because there are more questions in the survey, also, the time taken by the respondents to answer the question increases, this hereby reduces the rate. Thus, it is clear that there isa chance for non-response bias.

Statement C is false because the large sample size does not indicate the validity of the survey. However, the resultsb of the survey may be biased if the large sample is not the representative of the population

Statement D is True