Have some data of the following form:
X | Y
----+-----
3 | 42
4 | 57
6 | 92
11 | 119
19 | 316
(NOTE: The above table is made-up data)
What I'd like to do with MS-Excel is to plot 2 curves, one that treats values in col. 'X' as horizontal axis data, assuming it to be a linear scale, and another assuming it to be a logarithmic scale. Is this possible ? If so, how ?
Also, if I wish to extrapolate the value of Y, (using, what I hope would be a choice of multiple "models"), for a given value of X, s.a. X = 5 or X = 9, how can I do it ?
I'd believe this to be the typical curve-fitting problem, with the statistical extrapolation, but don't know enough of MS-Excel to get around.
Best Answer
You've asked two different (albeit related) questions here. You should consider splitting this into two separate questions.
In answer to your first:
You now have two identically formatted charts, showing the same data with the difference in how the horizontal scale is displayed, like this:
In short answer to your second, this is very easy to do in Excel. The simplest method would be to setup a table with your base X values (e.g. as you describe above), a "model cell", and in place of static Y values, you'd have a formula (e.g. X*mod = Y). You would then just plot the Y values, which would change whenever you updated the value in your "model cell". This can get pretty complex and sophisticated with some work (e.g. using a lookup table to preset the "model cell" values, or using contingency tables). But as I started this answer, this is really a second question that requires additional detail from you to properly answer.