If small samples can reveal something that large samples might not, why not just take small samples in every situation?

Andrew owns a store in polk county. his trade extends throughout river city, but not beyond the county limits. he sells his store to betty and, as part of the transaction, agrees not to engage in the same business anywhere in river city for a period of five years. a. the time restraint is likely reasonable. b. the geographic restraint is likely reasonable. c. the agreement likely violates antitrust laws and the provision is not enforceable. d. both (a) and (b).