Acell phone manufacturer chose 200 people at random and asked them whether they would purchase the newest model for $300. the manufacturer repeated this survey using the same method three more times.

do any of the surveys appear to be biased?

would purchase new model for $300? survey
1 2 3 4
yes 127 131 128 133
no 73 69 72 66

a.
yes, because the results from survey 1 differ the most from the other surveys’ results.

b.
yes, because the results from survey 4 differ the most from the other surveys’ results.

c.
no, because the sampling methods are all different but have about the same results.

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