# Re: st: RE: log to the base 2

 From "Raphael Fraser" To statalist@hsphsun2.harvard.edu Subject Re: st: RE: log to the base 2 Date Tue, 17 Oct 2006 15:29:07 -0500

Base 2 is probably the most widely used base in applied statistics.
One reason is that it makes interpretation of your model so much
easier. I suspect this has not come up in FAQ because users simply
calculate the base themselves.

My idea of a log function would be something like this: log(x, y).
Which would read, "log of x base y." Not to create a function for
every base. This is what I was looking for initially.

I guess it wouldn't hurt if I write a small program.

Raphael

On 10/17/06, Nick Cox <n.j.cox@durham.ac.uk> wrote:
What matters here is what StataCorp thought when
choosing which functions to implement.

The point is when to stop. If another base other than
e and 10 were to be supplied, it would certainly be base 2.
However, I don't think that logs base 2 are especially
often needed in statistical work -- if they were this
would be an FAQ because many others would have the
same question as you -- and as the work-around is easy
I guess StataCorp decided to stop short.

Nick
n.j.cox@durham.ac.uk

Raphael Fraser

> I thought the logs were so easy to calculate this would be a single
> standard function in Stata. I suppose you thought: if they are so easy
> to calculate why write a function.

> On 10/17/06, Nick Cox <n.j.cox@durham.ac.uk> wrote:

> > You hardly need any such function. The recipe
> > log(x) / log(2) or log10(x) / log10(2) will suffice.
> >
> > For example,
> >
> > . di log(8) / log(2)
> > 3
> >
> > Strictly just one log function is enough, but -log10()-
> > is a convenience for those preferring the unnatural.

Raphael Fraser

> > > I have been trying to find a function that can calculate
> the log of a
> > > number to base 2. I can't find one. Am I missing
> something here or am
> > > I not searching hard enough? Can any one help?
> > >
> > > I see log to base 10 and log to base e but what happen to the
> > > other bases?

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