Exercise: Polling

Question

4 points possible (graded)
We saw that if we want to have a probability of at least 95% that the poll results are within 1 percentage point of the truth, Chebyshev's inequality recommends a sample size of n=500 . This is very large compared to what is done in practice. Newspaper polls use smaller sample sizes for various reasons. For each of the following, decide whether it is a valid reason.

In the real world,

a) the accuracy requirements are looser.

Select an option
unanswered
b) the Chebyshev bound is too conservative.

Select an option
unanswered
c) the people sampled are all different, so their answers are not identically distributed.

Be careful in parts c) and d) (April 17): You are not asked whether the statement is true or false, but whether it would be a valid reason for Newspaper polls to use smaller sample sizes.

Select an option
unanswered
d) the people sampled do not have independent opinions.

Select an option