Rache

Hi everybody, I got a little complicated question, but I'll try to make it as clear as possible. For my thesis I am doing research on the impact of the shifts within GOLD classifications on the quality of life of COPD patients. The dependent variable is the quality of life and the independent variable is the GOLD classification. I only look at the GOLD 2011 and the GOLD 2015 classification, with the GOLD classification as a categorical variable: GOLD A, B, C and D. One of my sub-questions I have difficulties with is: 'To what extent does the quality of life change in the GOLD 2011 and GOLD 2015 classificationgroups from baseline to year 1? I do not know exactly what tests I should run in order to find an answer to this question. What I do know is that the knowledge about the (level of) quality of life within the GOLD classification can be found by running a One Way Independent ANOVA test (if the dependent variable is normally distributed) or Kruskal-Wallis test (if the dependent variable is not normally distributed) with the GOLD 2011 (ABCD) and GOLD 2015 (A BC D). My main research question is 'What is the relation between the quality of life of COPD patiënts and the different GOLD 2015 classificationgroups and in which extent does this differ from the GOLD 2011? Thanks in advance!