Finding missing coordinates in a non-linear graph? If I have the y value for the x values of 1, 2, 3, 7, and 9 in a graph, but I need all 1 through 12, how would I figure out the missing points?
 x  |  y
---------
 1  |  5
 2  |  6
 3  |  7
 7  | 10
 9  | 11

 A: It depends on the exact nature of the non-linear graph you expect. Is it a polynomial? Exponential? Rational? You need to inter/extrapolate the values in between and right after the data points you know, so you can use the general form of the type of function you need. Plug in the known data points, and then you'll get a system of equations you can solve for the unknown constants' values in the general formula. 
Word/PowerPoint are good for this kind of work; just go onto insert -> chart -> XY (scatter) and start imputing the data points. Then go onto the treadline option in the design tab and choose the type of function you want. It will give you the best fit for the function type (choosing a 5th degree polynomial in your case will guarantee you an exact fit, although sometimes it can be exact for lower degree polynomials.) as well as the function's equation (by ticking the appropriate boxes). You can then use the function to extrapolate/interpolate the values to the points you want by simply plugging in the values you want.
