EXAMINING SAMPLES

Any sample consists of a subset of the data in a population. This chapter shows how estimation and hypothesis testing allow us to draw conclusions about a population by examining a sample. The purpose of estimation is to make a good guess at the value of a parameter in the population. There are two kinds of estimates that we can make from the sample’s observations: point estimate and interval estimate. There are four steps in the process of statistical hypothesis testing. The first step is to formulate the hypothesis about the nature of the population that will be tested. Next, we take a sample from the population. Then, we calculate the probability of getting that sample if the hypothesis were true. In the final step, we reject the hypothesis as a description of the population if the probability of getting that sample assuming that the hypothesis was true is sufficiently small.