var app = angular.module('plunker', []);

app.controller('MainCtrl', function($scope) {
  $scope.name = 'World';
  
  $scope.MyRadioData = 'No';
});
<!DOCTYPE html>
<html ng-app="plunker">

  <head>
    <meta charset="utf-8" />
    <title>AngularJS Plunker</title>
    <script>document.write('<base href="' + document.location + '" />');</script>
    <link rel="stylesheet" href="style.css" />
    <script data-require="angular.js@1.5.x" src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.11/angular.min.js" data-semver="1.5.11"></script>
    <script src="app.js"></script>
  </head>

  <body ng-controller="MainCtrl">
    <p>Hello {{name}}!</p>
    
    <button ng-click="MyRadioData = 'Yes'">Yes</button>
    <button ng-click="MyRadioData = 'No'">No</button>
    <span ng-hide="MyRadioData == 'Yes'" data-for="MultiSelect1" data-role="validator">asdf</span>
  </body>

</html>
/* Put your css in here */