[lisualsethelp]

I know some of you guys are good at math and stats so if you could help my question is pretty basic.

Say you're doing a hypothesis test of two sample groups to determine if there is a statistically significant difference between the means. You have no reason to believe they should be different so by default your hypothesis would be no difference between the means of group x and y. Say you run this test and you find there is a statistically significant difference. And say your mean for x was 70 and your y mean was 60 (I'm just making these numbers up). Would it then be OK to run an addtional hypothesis test of X mean > Y mean and see if there is statistical significance? Or can you only run the X mean no different than Y mean and that's it?