A researcher predicts that an exercise intervention with patients who have respiratory problems will improve physical function, measured by muscle force and oxygen uptake. There was an intervention (N = 20) and a control (N = 20) group.

3. From those listed below, an appropriate statistical test to analyse these data is:

a) One-sample z-test

b) Paired t-test

c) Mann–Whitney test

d) Wilcoxon