sub correlation { print "\nWe are in the correlation subroutine\n\n"; my ($x_ref, $y_ref) = @_; my @x = @{$x_ref}; my @y = @{$y_ref}; my $lfit = Statistics::LineFit->new(); $lfit->setData(@x, @y); printf "a=%.4f, b=%.4f, R2=%.4f\n", $lfit->coefficients(), $lfit->rSquared(); return "a=%.4f, b=%.4f, R2=%.4f\n", $lfit->coefficients(), $lfit->rSquared(); } #### my ($y_axis_intercept, $gradient, $R2) = correlation(\@primarys, \@secondarys); #### Can't use an undefined value as an ARRAY reference at c:/Perl/site/lib/Statistic s/LineFit.pm line 191, line 164.