Am trying to do my own chart on google docs. Have just spent ages inputting daily consumption data and creating a chart. But all it is is zig zags. How do i create the fancy trendline ive seen in other charts? When i open the sheet or the chart view there appears to be no place for formula's.

https://spreadsheets.google.com/ccc?key ... 0SGw&hl=en

may be able to help, but I don't use google docs. You're looking for exponential growth (well decrease actually!)

alternatively, you could try the following trick:

a) Add 0.001 units to every daily unit count (so that you have no zeros)
b) Create a new column LN(x), where x is the unit count data
c) Plot the above against the days
d) create a straight line of best fit/trend. If you have the option to specify the intercept, then choose a value equal to your pre-TSM consumption

ACK - you people kill me with your do this, do that, click click click...

I have a chart out there somewhere that I think 14TR did for me. I'm sorry - I'd have to really swim back downstream to find it. Didn't know how to isolate & save it in the first place...no comment on my deficiencies puh-leez...and now I forgot my point! :-/

Nevermind! LOL

Hi 1-4 I understood everything you said up to 'you could try the following trick'
Think i'll have to go back to AJ