Call this function on the single product page with <?php echo sumobi_custom_show_average_star_rating(); ?>

gistfile1.php

<?php

function sumobi_custom_show_average_star_rating() {
	// make sure edd reviews is active
	if ( ! function_exists( 'edd_reviews' ) )
		return;
	
	$edd_reviews = edd_reviews();
	// get the average rating for this download
	$average_rating = (int) $edd_reviews->average_rating( false );	
	$rating = $average_rating;

	ob_start();
	?>
		<div itemprop="reviewRating" itemscope itemtype="http://schema.org/Rating" class="star-rating">
			<div class="edd_reviews_rating_box" role="img" aria-label="<?php echo $rating . ' ' . __( 'stars', 'edd-reviews' ); ?>">
				<div class="edd_star_rating" style="width: <?php echo ( 19 * $rating ); ?>px"></div>
			</div>
			<div style="display:none" itemprop="reviewRating" itemscope itemtype="http://schema.org/Rating">
				<meta itemprop="worstRating" content="1" />
				<span itemprop="ratingValue"><?php echo $rating; ?></span>
				<span itemprop="bestRating">5</span>
			</div>
		</div>
	<?php
	$rating_html = ob_get_clean();

	return $rating_html;
}