As part of a study of the development of the thymus gland, researchers weighed the glands of five chick embryos after 14 days of incubation. The thymus weights (mg) were as follows 12:
29.6 21.5 28.0 34.6 44.9
For these data, the mean is 31.7 and the standard deviation is 8.7.
(a) Calculate the standard error of the mean.
(b) Construct a 90% confidence interval for the population mean.