ABSTRACT
In Chapter 1 (Section 1.2), five types of research situation were identified. In the first, the researcher has two samples of scores and wants to know whether the difference between sample averages is significant. Here a two-sample test is appropriate. As an aid to choosing an appropriate test, we offered a provisional decision chart (Chapter 1, Figure 2), the important proviso being that the data must meet the requirements of the statistical model upon which the test is based. The first question in the flow chart concerns the number of groups or conditions. This chapter is partly concerned with the use of SPSS to carry out the tests recommended by the chart when there are only two conditions. In the fifth research situation described in Chapter 1, the researcher has only a single sample of scores, on the basis of which he or she wishes either to make an inference about the mean of the population or decide whether the distribution of the sample is sufficiently well fitted by a theoretical distribution (Chapter 1, Figure 6). This chapter will also describe the use of SPSS to make appropriate one-sample tests in such situations.
