Good afternoon. Firstly, I am not a statistician, so apologies if what I am asking isn't clear.
The RALES study "The Effect of Spironolactone on Morbidity and Mortality in Patients with Severe Heart Failure", published in 1999 is highly regarded, and has guided the management of heart failure since its publication.
The journal can be found Here if you're interested.
I take no issue with the study, but can't quite get my head around the Wilcoxon test used below:
"Three categories were used to assess changes in the symptoms of heart failure: improvement, no change, and worsening or death. The condition of patients who were in NYHA class III at base line was considered to have improved if they were in NYHA class I or II at the end of the study and considered to have worsened if they were in NYHA class IV (or had died). The condition of patients who were in NYHA class IV at base line was considered to have improved if they were in NYHA class I, II, or III at the end of the study; other patients in NYHA class IV at base line either had no change at the end of the study or died. In the placebo group, the condition of 33 percent of the patients improved; it did not change in 18 percent, and it worsened in 48 percent. In the spironolactone group, the condition of 41 percent of the patients improved; it did not change in 21 percent, and it worsened in 38 percent. The difference between groups was significant (P<0.001 by the Wilcoxon test)"
Is the Wilcoxon test the most appropriate test to use for this data? (as it has been used to measure a difference between groups as described above)
Is there a way to quantify the robustness result? and is there anything else I need to consider while drawing conclusions from this paragraph?
Thanks, Dan.
The RALES study "The Effect of Spironolactone on Morbidity and Mortality in Patients with Severe Heart Failure", published in 1999 is highly regarded, and has guided the management of heart failure since its publication.
The journal can be found Here if you're interested.
I take no issue with the study, but can't quite get my head around the Wilcoxon test used below:
"Three categories were used to assess changes in the symptoms of heart failure: improvement, no change, and worsening or death. The condition of patients who were in NYHA class III at base line was considered to have improved if they were in NYHA class I or II at the end of the study and considered to have worsened if they were in NYHA class IV (or had died). The condition of patients who were in NYHA class IV at base line was considered to have improved if they were in NYHA class I, II, or III at the end of the study; other patients in NYHA class IV at base line either had no change at the end of the study or died. In the placebo group, the condition of 33 percent of the patients improved; it did not change in 18 percent, and it worsened in 48 percent. In the spironolactone group, the condition of 41 percent of the patients improved; it did not change in 21 percent, and it worsened in 38 percent. The difference between groups was significant (P<0.001 by the Wilcoxon test)"
Is the Wilcoxon test the most appropriate test to use for this data? (as it has been used to measure a difference between groups as described above)
Is there a way to quantify the robustness result? and is there anything else I need to consider while drawing conclusions from this paragraph?
Thanks, Dan.