sub compare_bell_curves
my ($self,$m1,$sd1,$m2,$sd2) = @_;

my $upperbound = sprintf("%.1f", ($m1 + (1.75 * $sd1)));
my $lowerbound = sprintf("%.1f", ($m1 - (1.75 * $sd1)));
my $area = 10000;

my $data;
for (my $x=$lowerbound; $x < $upperbound; $x = $x + 1)
{
   $x = sprintf("%.0f", $x);
   my $posarg =  $self->int_gen_curve($x,$m1,$sd1);
   $data->[$x] = int($area*$posarg);
 }

# do the above again for the $m2 and $sd2
# then subtract $data1 from $data, any $data->[x]
# that remains positive is a point of difference