Ok I have to do a 2 sample t-test so i have 2 different sets of data that are similar to this.

boy grades = 90,87,77,97,64,76,88,93,83,79

girl grades = 100,95,69,77,85,89,78,90,66,81

alpha = .05

If i take the average of each set, I can find the x-bar but i need to find the mu in order to complete the test statistic. Any help is appreciated, thanks