This tip hides the submit quiz button until user marks the last question .
As soon as user marks last question submit button appears otherwiese it will remain hidden.

Please add this script  from wp-admin ->  wplms -> Footer  - >Google anaylitics code : 

  

<script>
jQuery(document).ready(function($){
$('.unit_content').on('unit_traverse',function(){ 
 $('.quiz_meta').on('progress_check',function(){ 
    if (typeof all_questions_json !== 'undefined'){ 
        var last = parseInt(all_questions_json[(all_questions_json.length-1)]); 
        if(localStorage.getItem(last) === null){  
          $('.unit_prevnext .col-md-6 .unit_button').addClass('hide');
        }else{
           $('.unit_prevnext .col-md-6 .unit_button').removeClass('hide');
        }
    }
  }); 
});
});
</script>