
26 Empirical Research in Software Engineering
1.8.10 Parametric and Nonparametric Tests
In hypothesis testing, statistical tests are applied to determine the validity of the hypoth-
esis. These tests can be categorized as either parametric or nonparametric. Parametric tests
are used for data samples having normal distribution (bell-shaped curve), whereas non-
parametric tests are used when the distribution of data samples is highly skewed. If the
assumptions of parametric tests are met, they are more powerful as they use more infor-
mation while computation. The difference between parametric and nonparametric tests is
presented in Table 1.4.
1.8. ...