Non-Parametric Methods

Parametric tests

Assume underlying statistical distributions in the data.

Therefore, several conditions of validity must be met so that the result of a

parametric test is reliable.

Nonparametric tests

Do not rely on any distribution. They can thus be

applied even if parametric conditions of validity are not met.

normal quantile plot

Is a graph of points (x, y) where each x value is from the original set of sample data, and each y value is the corresponding z score that is a quantile value expected from the standard normal distribution.

Spearman Rank Correlation Coefficient

Is a nonparametric statistic that uses ranks to determine if there is a relationship between two variables.

Chi-Squared Test of Independence

tests the null hypothesis that the row variable and column variable in a contingency table are not related