A biologist wants to test the null hypothesis that the mean mean wingspan of a certain kind of insect is 12.3mm against the altenative that it is not 12.3 mm. If she takes a random sample and decides to accept the null hypothesis if and only if the mean sample falls between 12.0mm and 12.6mm, what decision will she make if she gets xbar=12.9mm and will it be an error if
a) Mu=12.5mm:
(b) Mu=12.3mm?