sub do_work {
	my @working_block = @input_data[$start .. $stop];
	my @partial_output_data;
	$, = undef;
	$\ = undef;

	my $output_line = 0;
	for (my $i = 0; $i < @working_block; $i += $files) {
		# calculates the stddev of each slice and outputs the formatted resuls
		if (max(@working_block[$i .. $i + $files - 1]) == 0) {
			$partial_output_data[$output_line] = '0.00000E+00';
		} else {
			$partial_output_data[$output_line] = 
				sprintf('%.5E', stddev(@working_block[$i .. $i + $files - 1]) / 
				mean(@working_block[$i .. $i + $files - 1]));
		}
		$output_line++;
	}
	@ReturnData[$start / $files .. $stop / $files] = @partial_output_data;
	return;
}