Create a forecast estimate updated with actuals weekly

[Sayth Renshaw]

Hi

Wondering if someone has this knowledge, and please forgive my maths expressions.
If I want to estimate need results to achieve a goal at the end of a term updated weekly with real results how would I structure this?

So as an example to illustrate my thought process(which could be wrong) These are Bills results for the first to weeks.

Bills Goal = 60% after 5 weeks.
			
	wk1	wk2	wk3	wk4	wk5
Bill	54.5%	57.1%			

So say these are the results that get it to current.

wk1		wk2	
get	opp	get	opp
6	11	4	7

So 6/11 etc

I am thinking to achieve this I then need to estimate an average opportunity rate rounded up. (11 + 7)/2 = 9 so if we had a 5 week term

wk3		wk4		wk5	
get	avgopp	get	avgopp	get	avgopp
X	9	X	9	X	9

So doing it manually I would discover Bill needs 6 out of 9 each week, which results in:

sumget	28	0.622222222	result
sumopp	45		


But how do I structure this so that the new results when known for week 3 update and adjust the following estimates?

Thanks

Sayth