ruby-regress

ruby-regress is a tool for computing correlations and regression equations from two-variable input. It is designed to function as a drop-in replacement for Gary Perlman's regress, at least for those who use only the basic functionality that regress provides.

The problem with Gary Perlman's excellent |STAT programs is twofold:

• The only way of obtaining a copy is by emailing Perlman and asking for it.
• The distribution of modified copies is expressely forbidden.

If you need bulletproof robustness you're probably better off dealing with Perlman's terms of access and using |STAT; if you want ease of installation, try ruby-regress.

If you're using Gemcutter.org as a your gem host (hint: you almost certainly are) you can install ruby-regress using rubygems:

gem install ruby-regress

which installs the regress executable.

Download the most recent source from Github:

git clone git://github.com/doches/ruby-regress.git

then build and install the gem:

cd ruby-regress
rake build
sudo rake install

ruby-regress installs a single command line tool called regress, which reads from STDIN and prints a report containing the correlation coefficient, plus some descriptive statistics, to STDOUT. For example, if we have a file in the current directory called data.txt containing two datasets:

1   12.0
2   11.0
3   13.0
4   14.0

we can get the correlation coefficient between these two variables by:

cat data.txt | regress

which will dump a load of statistical information about the datasets to the terminal.