WHICH STATISTICS TO USE FOR MY DATA?

First notice that since the sample size is greater than 30, T test is equivalence to z-test. So you've actually picked up a z-test. The idea of using a matched pairs test can't be taken, since two groups are actually coming from two populations and not from the same one. You can also do a chi-square test to see if the standard deviations of two populations are equal or not. It will be equivalence to the t-test (or here the z-test) result. That's if the equality of two populations means is rejected by the t-test then the equality of two populations standard deviations must be rejected by the chi-square test, as well.