Which statistical test would be correct?

There were 2 study groups - an intervention group and a control group. Quality of life was measured at the interval level at BASELINE and at the END (so at 2 points in time) for both patients and partners.

The hypothesis is: "Regardless of study group, patients and their partners will have similar levels of quality of life at all data collection points."

What statistical test would be appropriate to test this? Could a paired t-test work? I'm supposed to perform a test on SPSS but im not sure anymore - the study groups and patient/partners variables keeps confusing me

Thank you in advance for any help or suggestions


TS Contributor
You could calculate the absolute within-partner difference at both time points
and then use mixed analysis of variance (with a repeated-measures factor and
a grouping factor).

With kind regards