OK here goes. It's actually to do with my work and ot has been driving me crazy. Imagine this:
Month No.sick days No of pupils Ave per pupil
Jan 10 100 .01
Feb 9 101 .089
Mar 5 98 .057
If i want to work out the average sick day per pupil for the 3 mths I simply added the no of sick days up for 3 mths =24
then devided it by the total for no of pupils =299
answer being 0.80. Alternatively I would have added the right hand column up and devided by 3.
Do you think this is correct. If you do I will show you what someone else did.