Sampling and Sampling Distribution
A new kind of alkaline is believed to last an average of 25 hours of continuous use (in a given kind of flashlight).  Assume that the population standard deviation is 2 hours.  Of a random sample of 100 batteries is selected and tested, is it likely that the average battery in the sample will last less than 24 hours of continuous use?  Explain.
Japan’s birthrate is believed to be 1.577 per woman.  Assume that the population standard deviation is 0.4.  If a random sample of 200 women is selected, what is the probability that the sample mean will fall between 1.52 and 1.62.