A local elementary school offers a morning kids' camp that runs from 9 a.m. until noon Monday through Friday. The camp director would like to know if evening camps would be better attended by the children in the community than morning camps.

Upon pickup, a random sample of parents was asked, "Do you prefer morning camp hours (9 a.m.-noon) or would you prefer evening camp (6 p.m.-9 p.m.)?" A majority of parents indicated that they prefer the morning camp hours.

a) What type of bias does this survey display? What is a possible consequence of this bias for interpreting the results of this survey?

Someone advised the camp director to take a separate random sample of parents in the community who do not currently send their children to the morning camp, and then compare the proportion of parents who prefer the evening camp for both groups.

b) If the camp director combined the two separate samples into one, what type of sampling method would best describe the resulting sample? Would this be a suitable solution to the problem identified in part (a)?

c) Suggest a different sampling method from the one described in part (b) that the camp director could use to determine if evening camps would be better attended than morning camps. What is a benefit of this method?