Toggle Checkboxes AngularJS

I am trying to make checkboxes appear when a button is selected and disappear when it is not. I am using Angular Material to build the app as well.

Any help is appreciated

HTML

<md-menu>
    <img src="/imagepathhere" ng-click="$mdMenu.open($event)">

    <md-menu-content ng-model="checkbox">
      <md-menu-item>
          <md-button value="group"><p>Add</p></md-button>
      </md-menu-item>

      <md-menu-item>
          <md-button><p>Delete</p></md-button>
      </md-menu-item>
    </md-menu-content>
</md-menu>

<md-content flex class="md-whiteframe-1dp" ng-model="checkbox">

  <md-list>
    <md-list-item layout="row">
      <img class="md-avatar" src="/imagepathhere" />
      <div flex>
        <h3>Babe Ruth</h3>
      </div>

      <md-checkbox ng-if="checkbox == 'group'" layout="row"></md-checkbox>

    </md-list-item>
</md-list>