Luc randomly selected 40 students and asked them whether they had ever gone snowboarding. he repeated this survey using the same method three more times.

do any of the surveys appear to be biased?

ever gone snowboarding? survey
1 2 3 4
yes 10 13 2 12
no 30 27 38 28

a.
yes, because the results from survey 3 differ significantly from results from surveys 1, 2, and 4, which agree.

b.
yes, because all four surveys do not have identical results.

c.
no, because although the results differ among the four surveys, the sample method used for all was the same.

d.
no, because all four surveys have about the same number of people saying “yes” and about the same number of people saying “no.”