STAT 1400 Lecture Notes - Lecture 2: Peromyscus, Sampling Distribution, Standard Deviation
Document Summary
A statistic computed from a random sample is a random variable (this means that it can change: a statistic is any number that is computed from data (i. e. mean, range, icr, etc. ) Averages are less variable than individual observations: sigma/square root of n is always going to be smaller than sigma, the standard deviation of the sampling distribution measures how much the sample. When a variable in a population is normally distributed, the sampling distribution of the sample mean is also normally distributed. The blood cholesterols of 14-year-old boys is ~ n(cid:894) = (cid:1005)(cid:1011)(cid:1004), = (cid:1007)0) mg/dl. The middle 99. 7% of cholesterol levels in boys is 80 to 260 mg/dl. The sampling distribution of average cholesterol levels is ~ n(cid:894) = (cid:1005)(cid:1011)(cid:1004), = (cid:1007)(cid:1004)/ (cid:1006)(cid:1009) = (cid:1010)(cid:895) mg/dl. The middle 99. 7% of average cholesterol levels in boys is 152 to 188 mg/dl.
