ABSTRACT
This chapter introduces the normal distribution and discusses means, modes and medians as average measures of a population. It also discusses sample variability and methods of measuring it with variance, standard deviation and standard error of the mean. The chapter presents the idea of confidence intervals and the t-distribution. The process of taking a few representative measurements and then trying to assign parameters to the whole group is termed statistics. Statistics involves trying to derive parameters which describe a population from a limited set of data points. These data points are assumed to be represenatative of the population. There are three main averages used to describe a population: the mean, the median and the mode. The arithmetic mean, or mean, is obtained by taking the sum of all the values and dividing it by the number of values present.
