NYCPHP Meetup

[Tim Gales]

Mitch,

Didn't you say you couldn't find a 
statistical extension for PHP?

Anyway, if someone needs one I found 
something at http://ftp.stat.ucla.edu/Software/5/

If anyone wants to use something like this, you 
should test it ( I would like to know how the 
tests go, as I am mildly interested in this).

the function:
void cdfnor(int *which,double *p,double *q,double *x,double *mean,
            double *sd,int *status,double *bound)

can calculate SD from P,Q,X and MEAN

that is to say you can figure out the standard deviation
given the normal(integral of) density(P), the range(Q), 
the (upper) limit of the normal-density, 
and the arithmetic mean (MEAN)

(how else would you get it -- right?)

It would seem the authors (of the extension) assume 
you have more than a passing acquaintance with 
cumulative normal distributions.

T. Gales & Associates
'Helping People Connect with Technology'

http://www.tgaconnect.com

                  x    2
         1      /   -t  / 2
     ---------- |  e         dt
     sqrt(2 pi) /
                 -inf