Paired vs unpaired samples t-test in crossover study I have to analyse a 2x2 AB/BA crossover study, in which every participant was administered drug A and then no drug at all, or vice versa.
There were two study visits and in each visit the peak glucose values after an oral mixed meal test were taken for each participant.
I am confused about the type of t-test I should use to find the treatment effect.
Some resources suggest an unpaired samples t-test link here,whereas the majority of previous studies I've read uses paired samples t-tests.
I understand that comparing all observations from Period 1 to Period 2 would require a paired samples t-test, but would that calculate the treatment effect or the period effect?

When dealing with before/after for the sample participant, it is a paired test, when comparing different participants then it is an unpaired test.
It looks like you have both a paired test, in the AB and BA parts, and then an unpaired test, comparing AB to BA part
