I have a survey that I want to display based on the selection in a picklist. The survey branches depending on which option is selected. I'd like to use jQuery to hide and show the pertinent survey questions but the .change function doesn't seem to be doing anything. I just started messing around with jQuery yesterday so please be patient with me if I am missng something obvious. I'm at  a loss... Any help would be appreciated. 

(Note: I have tried using a jQuery static resource and it did not make any difference.)

the javascript

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function(){
   $('#theQuestions').hide();
   $('#thePlan').change(function(){
      if ($('#thePlan').val() == 'PPO') {
         $('#theQuestions').show();
         $('#MAO').hide();
         $('#DSNP').hide();
         $('#CSNP').hide();
      }
   });	 
});
</script>

 the visualforce

<div class="theFields">
   <p><apex:outputLabel >Type</apex:outputLabel></p>
   <apex:inputField value="{!c.Plan_Type__c}" id="thePlan" />
</div>

<div class="greybox" id="theQuestions"> 
  
   <div class="ques">
      <p>General Question?</p>
      <div class="selRad">
         <apex:selectRadio value="{!c.Question1__c}" >
	    <apex:selectOptions value="{!items}" />
	 </apex:selectRadio>
      </div>
   </div>
   <div class="ques" id="MAO">
      <p>MAO Question?</p>
      <div class="selRad">
         <apex:selectRadio value="{!c.Question2__c}" >
	    <apex:selectOptions value="{!items}" />
	 </apex:selectRadio>
      </div>
   </div>
   <div class="ques" id="PPO">
      <p>PPO Question?</p>
      <div class="selRad">
         <apex:selectRadio value="{!c.Question3__c}" >
	    <apex:selectOptions value="{!items}" />
	 </apex:selectRadio>
      </div>
   </div>
   <div class="ques" id="DSNP">
      <p>DSNP Question?</p>
      <div class="selRad">
         <apex:selectRadio value="{!c.Question4__c}" >
	    <apex:selectOptions value="{!items}" />
	 </apex:selectRadio>
      </div>
   </div>
   <div class="ques" id="CSNP">
      <p>CSNP Question?</p>
      <div class="selRad">
         <apex:selectRadio value="{!c.Question5__c}" >
	    <apex:selectOptions value="{!items}" />
	 </apex:selectRadio>
      </div>
   </div>

</div>