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CHAPTER 5 Hypothesis testing and statistical significance 137
Figure 5.4 Scattergrams illustrating alternative underlying populations when no relationship is observed in a sample
a 61% probability of obtaining this pattern from a population resembling that shown in (a).
In this case we would probably decide that the population does in fact resemble population (a)
rather than population (b). There are other issues that we would need to address, however,
before we could come to this conclusion, such as whether we had enough participants in our
sample (see section 5.9 and Chapter 8).
5.2 Null hypothesis
We have just slipped a very important concept past you, which needs further explanation. The
null hypothesis is very important to the process of hypothesis testing. We explained earlier