Hi whatwhatwhat and welcome to the forum.

I found these problems confusing as you must assume there is no difference between the two populations. That is called the null hypothisis or H sub zeor. I always found the opposite *** different . Then using this 5 step approach you find there is only 1% chance that your assumption is possible. The reason for the 1% is that using probability it is not a good chance but possible. It is like a coin toss comming up heads 10 times in a row is possible but not very likely.

Read http://www.unc.edu/~jamisonm/fivesteps.htm