Question

A political party sends a mail survey to 1500 randomly selected registered voters in a community. The survey asks respondents to give an opinion about the job performance of the current president. Of the 1500 surveys sent out, 480 are returned, and of these, only 120 show that the respondent is satisfied with the president’s job performance.

1) The population is:________.
a) the 120 respondents satisfied with the president's job performance.b) the 480 respondents that answered the survey.c) all registered voters in this community.d) the 1500 registered voters in the community selected to receive this survey.2) The sample is:________.a) the voters in his district.b) the 1500 randomly selected voters receiving the questionnaire.c) the 120 voters surveyed that are satisfied with the president's job performance.d) the 480 surveys returned.3) This is an example of:________.a) a survey with little bias because 1500 voters represent an important part of his district.b) a survey containing non-response.c) a survey with little bias since people understand whether they approve of the president's job performance.d) All of the above.

Answer 1

a) The population is all registered voters in this community.

b) The sample is the 1500 randomly selected voters receiving the questionnaire.

c) This is an example of a survey containing non-response.

Explanation:

a) The population is usually the entirety of the units under study. From this question the survey interest is the population of registered voters in a community. And since that is the interest, all registered voters in this community of interest form the population.

b) The sample is usually from the population, hence, the 1500 randomly selected registered voters in this community formed the sample.

c) This is a good example of a survey with high non-response rate. As given in the question, out of 1500 questionnaires sent out only 480 were completed. That makes 32% response rate and 68% non-response. We are told that they are all registered voters in the community of interest and yet, they never returned a response.

We cannot say much about the bias of the survey. We are only told the sample selection was a random process and no further information about how the questionnaire was distributed is provided. Therefore, the bias in this sense is subjective!