use Statistics::Regression;

  # Create regression object
  my $reg = Statistics::Regression->new( 
    3, "sample regression", 
    [ "const", "someX", "someY" ] 
  );

  # Add data points
  $reg->include( 2.0, [ 1.0, 3.0, -1.0 ] );
  $reg->include( 1.0, [ 1.0, 5.0, 2.0 ] );
  $reg->include( 20.0, [ 1.0, 31.0, 0.0 ] );
  $reg->include( 15.0, [ 1.0, 11.0, 2.0 ] );

  # Print the result
  $reg->print(); 

  # Prints the following:
  # ****************************************************************
  # Regression 'sample regression'
  # ****************************************************************
  # Theta[0='const']=       0.2950
  # Theta[1='someX']=       0.6723
  # Theta[2='someY']=       1.0688
  # R^2= 0.808, N= 4
  # ****************************************************************

  # Or, to get the values of the coefficients and R^2
  my @theta = $reg->theta;
  my $rsq   = $reg->rsq;