Ok, I have 6 test grades: 70 74 80 82 68 76 and the average comes out to 75. Now, I need to figure out the standard deviation, which is square root of (sum of squares of these differences)/(class size). I did it this way: 
 $std = sqrt((70-75)**2+(74-75)**2+(80-75)**2+
             (82-75)**2+(68-75)**2+(76-75)**2)/6))

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Now, if I had a DAT file already containing the scores, $score, and I already have the variable $avg, is there a simpler way??

In reply to Is there a simpler way?? by yabba

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