Why is a logarithmic not always an option under trendline type?

I have 22 plots that are all a similar, logarithmic shape, yet only three of
them give me the option to add a logarightmic trendline.

The plots where the logarithmic trendline does work are perhaps closer to a
true logarithmic shape than those where it does not work, but not by much.

Does the logarithmic trendline only work when the shape is very close?

Do you have zero or negative x values?

mpd4 wrote:
> I have 22 plots that are all a similar, logarithmic shape, yet only three of
> them give me the option to add a logarightmic trendline.
>
> The plots where the logarithmic trendline does work are perhaps closer to a
> true logarithmic shape than those where it does not work, but not by much.
>
> Does the logarithmic trendline only work when the shape is very close?

--

Andy Pope, Microsoft MVP - Excel
http://www.andypope.info

at the start of each plot, there were a bunch of x values around zero, some
positive, some negative, some zero, but my plot was formatted so that i
didn't see negative values cause they were inconsequential. thanks a lot for
your help, i couldn't figure it out.

"Andy Pope" wrote:

> Do you have zero or negative x values?
>
> mpd4 wrote:
> > I have 22 plots that are all a similar, logarithmic shape, yet only three of
> > them give me the option to add a logarightmic trendline.
> >
> > The plots where the logarithmic trendline does work are perhaps closer to a
> > true logarithmic shape than those where it does not work, but not by much.
> >
> > Does the logarithmic trendline only work when the shape is very close?
>
> --
>
> Andy Pope, Microsoft MVP - Excel
> http://www.andypope.info
>