I am trying to check to see if a value is in an array

I am trying to populate checkbox and then check them if a value is in an array.

Here is the code. I ran print_r on the $_SESSION arrays and I am representing them here

$_SESSION['inservice']['inservicepositionclasses']=Array
(
    [0] => Array
        (
            [inservid] => 16
            [positionclassid] => 1
        )

);

$_SESSION['positionclasses']['classes'] = Array
(
    [0] => Array
        (
            [positionclassid] => 4
            [positionclass] => Cardiology technician
        )

    [1] => Array
        (
            [positionclassid] => 3
            [positionclass] => CNA
        )

    [2] => Array
        (
            [positionclassid] => 2
            [positionclass] => LPN
        )

    [3] => Array
        (
            [positionclassid] => 1
            [positionclass] => RN
        )

);

Here is the foreach loop to set up divs with labels and checkboxes.

<?foreach($_SESSION['positionclasses']['classes'] as $positonclass){
    $checked='';
    if(is_array($_SESSION['inservice']['inservicepositionclasses']))    {
        if(in_array($positonclass['positionclassid'],$_SESSION['inservice'}['inservicepositionclasses'])){ 
         $checked = 'checked="checked"';
        }
 }?>
<div class="width330">
    <label for="positionclassids" class="width250 inlineblock"><?echo $positonclass['positionclass'];?></label>
    <input type="checkbox" name="positionclassids[]" disabled="disabled" <?echo $checked;?> value="<?echo $positonclass['positionclassid'];?>" />
</div>  

It doesn't seem to be working as the checkbox with the label RN that should be getting checked and it isn't. Does anyone see anything wrong with this logic?