Biostatistics 103: qualitative data - tests of independence.

Correspondence to: Y H Chan Tel: (65) 6317 2121 Fax: (65) 6317 2122 Email: chanyh@ cteru.com.sg Parametric & non-parametric tests(1) are used when the outcome response is quantitative and our interest is to determine whether there are any statistical differences between/amongst groups (which are categorical). In this article, we are going to discuss how to analyse relationships between categorical variables. Table I shows the first five cases of 200 subjects with their gender and intensity of snoring (No, At Times, Frequent and Always) and snoring status (Yes or No) recorded.