Thread: OMG please help! (standard deviation)

3 instructors are comparing scores on their finals; each has 99 students. Class A:, one student got 1 point, another got 99 points, and the rest 50 points. Class B: 49 students got a score of 1. one student got a score of 50, and 49 students got a score of 99. Class C: one student got a score of 1, one student got a score of 2, one student got a score of 3, and so forth, all the way through 99.

Im trying to find the average of each. I got class A & B, but cant figure out how to calculate C!

Class A: (1x1) (1x99) (97x50)= 1+99+4850 = 4950/99 = 50

Class B: (1x49) (1x50) (49x99) = 49+50+4851 =4950/99 = 50

Class C: (1x1) (1x2) (1x3)......???

I could write it all out but that would take forever...any easier way?

Help is greatly appreciated!

Karl Friedrich Gauss has figured this out for you.