Value from a Graph

[pathfinder.k]

Hi all,
in one of my calculations, I am calculating value 'X' in spreadsheet, then based on 'X' I am supposed to get the value 'Y' from a graph, then use value 'Y' in further calculations. Can I make excel to look up value 'Y' based on 'X'??

 

[Jon Peltier]

You can predict Y based on a regression of the known X and Y values. The predicted Y is given for the new X using:

=TREND(<known Y values>,<known X values>,<new X>)

replace my terms in brackets with cell reference to the appropriate ranges.

 

[Analyse-it]

Hi all,
in one of my calculations, I am calculating value 'X' in spreadsheet, then based on 'X' I am supposed to get the value 'Y' from a graph, then use value 'Y' in further calculations. Can I make excel to look up value 'Y' based on 'X'??

It's not clear from your question whether you need graph/chart digitizer software, to determine X/Y values from a static chart graphic, or whether you are referring to regression, to determine the formula for predicting Y from X?

Can you clarify? I assume you're referring to regression. If so, is the relationship between X & Y linear (a straight line)? If it is you can use Excel's linear regression function LINEST.

 

[pathfinder.k]

I was looking for what you are refering to as regression, I got a solution. I plotted my values as point scatter, and fitted a curve on it with R square as close to 1 as possible and used the polynomial equation for further processing... I am all set for now.