[Numpy-discussion] Questions about some of the random functions

[Robert Kern]

On Fri, Aug 15, 2008 at 17:26, Alan Jackson <alan@ajackson.org> wrote:
> Just a question - I'm gradually working through the distributions for
> the documentation marathon and I realised that there is a whole nest
> of them named "standard-xxxx".
>
> For several (e.g., normal) they are just the regular distribution with all the
> parameters except size set to "standard" values.

Not quite. Rather the regular distributions are built up from the
standard version by transformation.

> So my first question is - why? They seem very redundant.

At the C level, they sometimes exist because they are components of
other distributions that don't need the "x*1.0 + 0.0" waste. At the
Python level, they usually exist for backwards compatibility with the
libraries I was replacing or because I thought they would be useful
for Python-level implementations of some distributions in scipy.stats.

> Second question - why is there is a "standard-t" for Student's T-test
> (or the distribution associated with it) but no corresponding "t"
> distribution.

Apathy, to be honest.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco