I have, for example, 4 columns of data: column 1-a,b,b,c,d,c,e,f,g,g column 2-apples,bananas,oranges,grapes,grapes,bananas,bananas,apples,oranges,bananas column 3-1,2,3,4,5,6,7,8,9,10. For each individual value of column 1 (a through g) I want to average the values in column 3 that correspond...