Uncaught ReferenceError: jQuery is not defined

Hi, your plugin causing my site with error: Uncaught ReferenceError: jQuery is not defined

Below is the script causing the error:

<script type=”text/javascript”>jQuery(function($) { $( ‘.add_to_cart_button:not(.product_type_variable, .product_type_grouped)’ ).click( function() {
_gaq.push([‘_trackEvent’, ‘Products’, ‘Add to Cart’, ($(this).data(‘product_sku’)) ? ($(this).data(‘product_sku’)) : (‘#’ + $(this).data(‘product_id’))]);
});

});</script>