Question

what does it mean if your sample mean is greater/or less than your population mean? obviously I have to reject the null for both circumstances but is there anything I can conclude about the population?

Answer 1

No you cant make a conclusion just on the basis of  sample mean which is greater/or less than your population mean to reject the null hypothesis. You have to make a hypothesis test to calculate test statistic and then by comparing test statistics either using p value method or critical value method ,you can make a conclusion whether to reject the null hypothesis or not. One more point should be noted that if a test is statistically significant it doesn't mean it will be practically significant. It may or may not be practically significant.