The gestation time for humans has a mean of 266 days and a standard deviation of 25 days. If 100 women are randomly selected, find the probability that they have a mean pregnancy between 266 days and 268 days.
Suppose that the mean gestation time for the 100 women selected at random was =265 days. Suppose the researchers take another sample of 100 women. Would you expect the mean and the standard deviation of this new sample to exactly the same (i.e. =265 days)?
Suppose the researchers were able to collect gestation time for an additional 100 women (total sample size is now n=200).
How would doubling the sample size affect the standard error (SE) of the mean?
SE would decrease.
SE would increase.
SE would stay the same.