How to calculate intrapair differences?

Hello,

I've got a 12 pairs of twins. Twin 1 has a specific score on a task, and twin 2 has a specific score on the same task. I want to calculate the intrapair differences voor these 12 pairs. How do i do this? (see picture)

Answer 1

[Image Analyst]

Can't you just subtract the two arrays?

diffs = twin1-twin2;

or am I missing something? Surely it can't be that trivial. Did you leave something out?

Answer 2

[Star Strider]

You have an unpaired design, so you have to use the appropriate statistical test. (I did not enter your data, so I have done no calculations on them and do not know if they are normally distributed.)

If they are normally distributed, you can use an unpaired t-test. If they are not, use a Wilcoxon rank-sum test.