Phaser Create sprite group at interval

[edus101]

How can one create group sprite at intervals? 

Here is my code

<code>

 function createPlate() {
    this.add.group ({
      key: 'goodPlate',
      repeat: 4,
      setXY: {
        x: 70,
        y: 100,
        stepX: 120,
        stepY: 20
      }
    });
   }

  this.time.events.loop(3000, createPlate, this);

</code>