average.php

<?php
/**
 * Function: Average
 * Calculates average of values taken from custom fields out of a WordPress loop. Built of Jason ;)
 * Author: Baki Goxhaj
 */
function average( $post_no );
	$no = 0;	
	$query = new WP_Query('posts_per_page=' . $post_no ); while( $query->have_posts() ) : $query->the_posts();
		
		// Adding
		$no = $no + get_post_meta( $post->ID, 'cutom_field_name', true );
		
	endwhile;
	
	//Calculate Average 
	$average = $no / $post_no;
	
	echo $average
}
?>