averaging months

[PMRetired2012]

what i want to do is.
i want a foumula that will let me to get a rolling average for a month as i add numbers for each week. that total will be in one cell. I want it to be able for it to figure a average for week 1,2,3,4 so that I will have a current average each week.
Example:

week 1 attendance 20
week 2 atten 45 20 + 45= 65...65/2= 33 adverage so far for month
week 3 attendence 25 20+45+75=..140/3=46 adverage so far for month
week 4 attendence 95 20+45+25+95=180/4=180/4 = 46.25 adverage for the whole month.
So another words i need a formula that keeps a running total for each week till we get to week 4 and that represents the total monthly total for that month

Thanks

 

[RasGhul]

Hi,

Maybe this?

Book1
	A	B	C
1	Week #	Attendance	r-AVG
2	Week1	20	20
3	Week2	45	32.5
4	Week3	25	30
5	Week4	95	46.25
Sheet1

Cell Formulas
Range	Formula
C2	=AVERAGE($B$2:B2)