A quality of life test was given to a group of end stage renal patients just prior to their first (initial) hemodialysis treatment. The same test was given to the same group of patients 2 years later. The quality of life instrument that was used ranked responses on a scale from 1- 4 ('low' to 'very high' quality of life). The results indicated higher quality of life prior to the start of hemodialysis, p = .04. What statistical test do you think was used to determine this?

A.Friedman Test

B. Independent t-test, also called the student t-test

C. Mann-Whitney U test

D. Phi coefficient

E. Wilcoxon signed-rank test