chapter  8
17 Pages

The Essentials of Probability

It has been said facetiously that in life the only certainties are death and taxes; all else is uncertain. In statistics, as in life, there are few certainties. The notion of uncertainty is essential to an understanding of inferential statistics. We will be using the descriptive statistics that we have already learned in the first seven chapters to describe the data to which we have immediate access-the sample data. Based on what we see in the sample, we want to be able to make reasonably valid statements about the population, to which we do not have immediate access. Furthermore, we want to minimize the likelihood that our generalizations are way off target. Probability is one of the tools that will assist us in this task.