# PSYB01H3 Chapter 9: chapter 9 notes

## Document Summary

Samples may be drawn from the population using probability sampling or nonprobability sampling techniques. When it is important to accurately describe the population, you must use probability sampling. Much research, however, is more interested in testing hypotheses about behaviour. Here, the focus of the study is the relationships between the variables being studied and testing predictions derived from theories of behaviour. In such cases, the participants may be found in the easiest way possible using nonprobability haphazard or convenience sampling methods. In general, increasing your sample size increases the likelihood that your results will be statistically significant because larger samples provide more accurate estimates of population values. To manipulate an independent variable, you have to construct an operational definition of the variable. That is, you must turn a conceptual variable into a set of operations specific instructions, events, and stimuli to be presented to the research participants.