It is sometimes difficult to give an answer to these kind of questions, because I am not sure if your question is a question about Excel or a more generic question about statistics.

It often seems that these questions are more about statistics than Excel. If that is the case, rather than re-write an entire lesson on t-tests, I will point you to this tutorial (or put something like "t-test difference of means" into your favorite search engine): http://stattrek.com/hypothesis-test/...-in-means.aspx From this, the main variables that go into this kind of t-test are A) the two means and B) the standard deviation/variance of each mean. The null hypothesis is usually "mean1-mean2=0" and the alternative hypothesis is "mean1-mean2<>0".

If you are looking for help with Excel's built in statistics functions (including the various T.xxx() functions, I would first suggest the main Excel help files: https://support.office.com/en-us/art...__toc309306716

Review that information. If there is something you are still having trouble understanding and implementing, let us know where you are stuck and we will help as best we can.