The lengths of pregnancies are normally distributed with a mean of 263 days and a standard deviation of 25 days.
If 50 women are randomly selected, find the probability that they have a mean pregnancy between 262 days and 267 days.
If 100 women are randomly selected, find the probability that they have a mean pregnancy between 262 days and 267 days.
Explain why increasing the sample size changed the probabilities from part (i) to (ii).