Im not sure weather this is really an advanced statistcs problem. Ive had lots of statistcs class but could find a good solution yet, therefore I picked this channel..

Proble;

I have a porfolio with several buildings and a know variable, lets call it x. Also I have the area for every building. Now I would like to take the weigted mean for x, weigted with the area of each building. I did this in the following way:

Area of building:

s

k

Variable x:

x1

x1

weighting factor:

s/F

k/F

Total area of all building: F

The formula for my weighted mean goes the following way:

Mean (x1 * s/F + x2 * k/F).

The Problem ist that the mean of the variable x now has another power compared to when I look at the x seperately or take the normal mean of x. So is there a better way to calculate that mean of should I multiply with some factor here?

I also have an Excel sheet, where everything would be in. However I dont see how I could upload that..

Thanks for the help.