Lab 4.3: Glossary

The Central Limit Theorem: Basically, the Central Limit Theorem states that if certain assumptions are satisfied, then no matter what distribution a population has, means of data from that population tend to be normally distributed. Mathematically, if are independent random variables from the same distribution with mean and variance and if

,

then for large n, has approximately a N(0, 1) distribution.

Normal Quantile Plots: A normal quantile plot is a scatterplot in which the data are plotted against their associated normal quantiles. If the data are normal, the plot should resemble a straight line.

Cauchy Distribution: The Cauchy distribution is an example of a distribution for which a variance is not defined (In fact, a mean is not defined for it, either.) The probability density function of the Cauchy distribution model is