An absentminded (and not too clever) scientist friend of yours has just analyzed his data, and he has two numbers—25.4 and 2.54—written on a scrap of paper. He says: “I remember that one of these is the standard deviation of my data and the other is the standard error of the mean, but I can’t remember which is which. Can you help?”

a. Which number is the standard deviation and which is the standard error of the mean?

b. What was your friend’s sample size?