For the attached file, find:
  1. For variable PAY, calculate median and SD by denial code, but only for denial codes that have > 5 cases in them
  2. Within denial category calculate frequencies of cases by (median +/- [x*SD]) categories, where x=1,2,3. For example, Group 1 = median +/- 1*SD; Group 2 = median +/- 2*SD; Group 3 = median +/- 3*SD.