It seems this is more a question for DCDFLIB than it is a Perl question.

However, if you want to manipulate the mean and variance, isn't that just a matter of arithmetic? You just normalize your incoming data based on a mean and a variance down to a standard distribution where the mean is 0 and the variance is 1, and go from there.

Not that I remember that much -- my last Stats class was over 20 years ago. ;)

ps: You can link to a CPAN module using [cpan://{CPAN module name here}] like this: Math::CDF.

The underlying DCDFLIB routine cdfnor() actually does take mean and stddev parameters, but the XS code (Perl binding) which calls the DCDFLIB routine uses hardcoded values for mean and stddev (0.0 and 1.0). This is no big problem, however, as you can easily scale/displace the return value yourself. Just multiply by the stddev, and add the mean, e.g.

use Math::CDF qw(qnorm);

for my $p (0.33, 0.67) {
    print qnorm($p) * 2.5 + 44, "\n";
}
[download]

which gives

42.9002170858169
45.0997829141831
[download]

Thank you! Thank you! Works great!