An agronomist selected six wheat plants at random from a plot, and then, for each plant, selected 12 seeds from the main portion of the wheat head; by weighing, drying, and reweighing, she determined the percentage moisture in each batch of seeds. The results were as follows55:
62.7 63.6 60.9 63.0 62.7 63.7
(a) Calculate the mean, the standard deviation, and the standard error of the mean.
(b) Assuming the percent moisture in each batch follows a normal distribution, construct a 90% confidence interval for the population mean.