Probability

Abstract

In this chapter we will discuss probability. In the previous chapters we examined the methods of description of data but it is not sufficient to have data or to know where the data can be found and describe it. Statistical inference involves drawing conclusions about a population from a sample of data, which is obtained from a population. If we want to understand sampling procedures and implications for statistical inference firstly probability theory needs to be examined because, for example, each member of the population has a particular probability of being in the sample. In many cases samples are randomly chosen from a population. In fact, if a second sample were selected it would almost certainly be different from the first. In simple random sampling, the probability of being sampled is the same for all members of the population.