PHP and HTML – Get Average Review Star Rating Score in Text

Please goto list.phtml file and edit path of magento root directory: app\design\frontend\MyPackage\MyTheme\template\review\product\view\list.phtml

Add the below code as you require to display on product page's review section of front-end after admin configure review rating summary.

<?php  
    $_product = Mage::registry('product'); 
    $_productId = $_product->getId();
    $storeId = Mage::app()->getStore()->getId();
    $summaryData = Mage::getModel('review/review_summary')->setStoreId($storeId)->load($_product->getId());  
    $reviewsCount = Mage::app()->getLayout()->createBlock('review/product_view')->getReviewsCollection()->getSize(); 

    ?> 
    <div class="review-star-rating">
            <div class="star-rating"><?php echo (($summaryData['rating_summary'] * 5) / 100) ; ?></div>  
            <div class="rating_text"><?php echo $this->__('Average Rating Based on '.$reviewsCount.' ratings') ?></div> 
    </div>

Hope this helps you.

You can add in rating_option table but from it may get conflict with already exiting customer ratings and reviews. fields are : option_id rating_id, code, value, position

If you want to install fresh magento script then in set up file.

magento\app\code\core\Mage\Rating\data\rating_setup

You will find for loop in it change it to your digit.

for ($i = 1; $i <= 5; $i ++) {
        $optionData[] = array(
            'rating_id' => $ratingId,
            'code'      => (string)$i,
            'value'     => $i,
            'position'  => $i
        );
    }

But this only works at the time of module installation. You need to change this before set up magento.