Iused 57 points to put this question if you answer, you get part of that! 4
find the
3. 20, 16, 20, 17.5, 19.5, 18, 23
4. 21, 20, 24, 22, 22, 22, 16
5. 100, 90, 72, 95, 85, 83, 89, 81, 86, 93, 98
6. 4, 3, 1, 1, 2, 2, 3, 3, 2

To find the mean, you add up all the numbers and divide by the number of terms in the set. So...
3. (20+16+20+17.5+19.5+18+23) / 7 = 134 / 7 = about 19.14285714 or 19 and 1/7
4. (21+20+24+22+22+22+16) / 7 = 147 / 7 = 21
5. (100+90+72+95+85+83+89+81+86+93+98) / 11 = 972 / 11 = about 88.363636... or 88 and 4/11
6. (4+3+1+1+2+2+3+3+2) / 9 = 21 / 9 =2 .333... or 2 and 1/3