my $id;   # ??
foreach my $window ( @{ $data{$id} } ) {

  # only pass windows with > min number of stats (i.e. >1 for now), and
  # of course we also ignore any 'undef' windows.
  next unless scalar @{ $data{$id} }[$window] >= 2;

    foreach my $individual ( keys(%data) ) {


    my $segsites = Bio::PopGen::Statistics->segregating_sites_count( \@{ $data{$id} }[$window] );
    my $singletons = Bio::PopGen::Statistics->singleton_count( \@{ $data{$id} }[$window] );
    my $pi = Bio::PopGen::Statistics->pi( \@{ $data{$id} }[$window] );
    my $theta = Bio::PopGen::Statistics->theta( \@{ $data{$id} }[$window] );
    my $tajima_D = Bio::PopGen::Statistics->tajima_D( \@{ $data{$id} }[$window] );
    my $D_star = Bio::PopGen::Statistics->fu_and_li_D_star( \@{ $data{$id} }[$window] );
    my $F_star = Bio::PopGen::Statistics->fu_and_li_F_star( \@{ $data{$id} }[$window] );

    # output follows:
    say $out_file "Population: $cont\tChromosome: $chr_num";
    say $out_file "Seg sites\tSingletons\tPi\tTheta\tTajima's D\tFu & Li F*\tFu & Li D*";

    # to account for invariant sites, divide stats by window size (i.e. 100_000)
	my @stats = qw($segsites $singletons $pi $theta $tajima_D $F_star $D_star);
	foreach my $stat (@stats) {
		print $out_file $stat / 100_000, "\t"
		}
	print $out_file "\n";

    }
}