Assume you obtaind the following exam scores from six students: 97,90,86,93,76, and 86
a. find the mean for the scores. i got 88 for the mean.
b. demonstrate that σ (χ - x bar) = 0 for these scores.
c. find the value of σ (χ - x bar)² for these scores.

A) The answer is 88
B)I don't know how to do it
3)I don't know 
Sorry I tried

A) 88 is correct
B) I think we are looking for variance which would be 43.6666- other wise I don't really understand what they are asking for.
C) I think this is sum of differences which would be 262.

I don't know if this is what they are asking for however. so I'm not 100% sure if this is correct, sorry.