Small Sampling Theory
	q When the sample size is smaller than about 30 (N<30), we can not use the normal distribution to describe the variability in the sample means. q With small sample sizes, we cannot assume that the sample-estimated standard deviation (s) is a good approximation to the true standard deviation of the population (s). q The quantity            no longer follows the standard normal distribution. q In stead, the probability distribution of the small sample means follows the “Student’s t distribution”.