I need to check for normality of my data. My independent variable is age and dependent variable is attitude. When I run the Kolmogorov/Shapiro test, I receive a warning that to say that some of the ages have been committed i.e. Attitude is constant when Age is 22. It will be included in any box plots but other output will be omitted. So I am not receiving any results for some of the ages in the Kolmogorov/Shapiro test or Skewness and Kurtosis.
Am I doing the test correctly?
This how I have done it: In SPSS go to analyze, descriptive, explore. I move attitude to dependent list and age to factor list.
Or should I run age and attitude separately?