0
$\begingroup$

Possible Duplicate:
How should I transform non-negative data including zeros?

I have a question:

Suppose we have a data point $(0,10)$. We then convert to a log scale. Excel gets rid of this data point since the minimum x-value is $1$. How do we keep this data point?

Edit. Can't you change the x-coordinate to $1$? So instead we have $(1,10)$ instead of $(0,10)$. The rest of the values are not changed.

$\endgroup$

marked as duplicate by Peter Flom, gung, Andy W, whuber Oct 11 '12 at 14:27

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

4
$\begingroup$

The convention is to add a small constant to all values in a vector before taking the log, whether it's base-10 or base-e. So you might use, e.g., log(x+1) or log(x+.001), depending on which would have the least effect given the range of values you're dealing with.

$\endgroup$
  • $\begingroup$ @ronaldo2: Can't you just change the x-coordinate to 1? $\endgroup$ – Rhubarb Joker Oct 11 '12 at 13:35

Not the answer you're looking for? Browse other questions tagged or ask your own question.