A shipment of 900 small lab mic arrives at the animal care facility with a nominal weight of 10 g per mouse. A sample of 30 mics is selected and weighed. The average weight of the sample is 13g. From...

A shipment of 900 small lab mic arrives at the animal care facility with a nominal weight of 10 g per mouse. A sample of 30 mics is selected and weighed. The average weight of the sample is 13g. From past shipments, it is known that the standard deviation of weight among mic is 5 g. How many mics need to be sampled to ensure that the 95% confidence interval has a margin of error of 2?