1. To compare two groups which are numerical but not normally distributed 2. To compare two groups..

1. To compare two groups which are numerical but not normally distributed 2. To compare two groups which are categorical 3. To assess whether a variable has changed between two time points in numerical and normally distributed data 4. To assess whether a variable has changed between two time points in numerical but not normally distributed data 5. To compare two groups which are numerical and normally distributed.