Chi-square Test and Its Utility in Forest Ecology Studies

In forest ecological studies, the data are often collected as nominal variables which can be summarized as frequency data. For this kind of nominal data, the chi-square test statistic can be used to evaluate whether the study groups are independent or not in their occurrence. This frequency data are arranged in a 2 x 2 table or with more rows and columns tabular format to undertake Chi-square test. Frequency or counts data of exclusive categories are used to test their independence/association by testing their proportion of occurrence in the rows and columns of the Chi-square table. The article includes the details on the data that can be used under Chi-square test through case studies, assumptions associated with the test, how the test and associated p-value can be achieved by simple manual calculation without any statistical program.