I'm doing a pre-test and post-test comparison of sexual health knowledge using paired sample t-test.So I measure participants knowledge before camp and after a camp. My t test showed pre and post test are significantly different but it does not meet the assumption of correlation. My pre-test and post-test are not correlated, r = 0.081, almost could be considered zero correlation. Could anyone help to explain or interpret?
It is odd that pretest and posttest results are not correlated (see below), but it has nothing to do with whether they are different and there is no assumption that two variables have to be correlated to do a statistical test of the difference.
You are doing a paired t-test. This test, in particular, does not assume that the pre and post values are correlated.
However, if they are not correlated, then an independent samples t-test would give very similar results to a paired t-test.
I would be concerned at the lack of correlation - not because of worries about the t-test but because of worries about the reliability of the sexual health knowledge test. I'd examine the data carefully to try to figure out this odd result. Did all the people get similar scores on either the pre or post test?