Bags checked for a certain airline flight have a mean weight of 15 kg with a standard deviation of 5 kg. A random sample of 60 bags is drawn. a) What is the probability that the sample mean weight is...

Bags checked for a certain airline flight have a mean weight of 15 kg with a standard deviation of 5 kg. A random sample of 60 bags is drawn. a) What is the probability that the sample mean weight is less than 14 kg? b) Find the 70th percentile of the sample mean weights. c) How many bags must be sampled so that the probability is 0.01 that the sample mean weight is less than 14 kg?