The second article in this three-pan series on choosing the correct statistical test focuses on the use of parametric tests. Next week, the final article discusses the uses of non-parametric tests

Statistics are all about making simple summaries of data. Some aspect of the data, summed up as a single number, is called a statistic. Statistical analyses can be of two basic types: descriptive statistics, whereby the researcher collects a set of data and then describes it in terms of its most important features (1), and inferential statistics, which enable the researcher to make inferences beyond the data in front of him or her.