future consumption estimation Here's the problem:
My boss asks for past 12 electricity bills, in order to create an acurate customer's profile, according to their consumption (in KWh). Then he makes a better deal for them.
An electricity bill is received every 4 months. So the comsumption is for the past 4 months also.
What I want to do, is to find the future consumption, by having just one or two bills and save time in closing the deal.
Could you please inform me, whether there is a specific type, or what could I do to estimate it?Thank you in advance for your guidance.
 A: I would comment this, but I need +50 rep.
I'm not trying to answer your question with more questions but here are a few things:


*

*I'd say one or two data points is a poor indication of future power use. Particularly with 4 months, as the seasons change. 

*You could plot the data points, and determine a function for the graph.
For example, if you wanted a very basic way of doing it, if you had two data points, get the $y = mx+c$ and simply extend the line, and see where it is at the next 4 months. 

*Plot it in excel, with time on the $x$ axis and KWh on the $y$ axis. Adjusting for inflation is up to you. Then plot the line connecting the data points. 


This link http://www.homeandlearn.co.uk/excel2007/excel2007s3p13.html shows some great stuff on future value predictions.
Your accuracy in this will depend on how many variables you're willing to calculate for. Like I said, how many data points you choose, inflation, season change etc
Making a prediction off one data point won't achieve much and will be an educated guess. 
