Show/Hide checkboxes based on values in an array

New to Angular and javascript and been wracking my brain for 2 days. I have a table in html where I need to show and hide checkboxes. Each row has 5 checkboxes. What will be visible depends on the FieldName and the index in the FieldName's array. I've commented the code below, and I hope it explains what I've tried.

The angular code on the html page looks like this, with the number ranging from 0 to 4. -- ng-show="ShowCheckbox(info.FieldName, 0)"

The javascript looks like --

$scope.ShowCheckbox = function (FieldName, index) {       
// FieldName is "MandatedMaterials", "AgencyAgmt", etc.

    var MandatedMaterials = [true, true, false, false, false];
    var AgencyAgmt = [true, true, false, false, false];

    return FieldName[index];  
    // This is what I really really want to work.
    // Only MandatedMaterials[2] and AgencyAgmt[3] return false

    // My experiments to narrow down the problem.
    //if (FieldName == "MandatedMaterials")          
    // works, so FieldName is coming from index.cshtml

    //if (index == 3)
    // works, same thing as above

    //if (MandatedMaterials[0] == true)              
    // works, in that it showed all checkboxes

    //if (AgencyAgmt[0] == true)                     
    // works, same as above

    //if (FieldName[0] == true)                      
    // NOPE -- should show all checkboxes, but instead none

    //if (FieldName[0])                              
    // works, in that it shows all checkboxes

// For testing purposes I had "if" code to return true or false for the 
// commented out statements above. This meant those bits of code would 
// show all the checkboxes.
}

If you could help me to get the appropriate checkboxes shown and hidden, I would very much appreciate it. Thanks.