Angular JS, get random array values on click

I'm currently building an app where you can make neat trading cards as my introduction into AngularJS. Currently I have a set array of stats that people can choose from to build onto their character, but I'd like to make the feature more random/automated.

Currently I am spitting out the buttons to set the stats this way:

<p ng-repeat="power in cardPowers">
      <a href="" ng-click="cardStats(power.attack,power.defense,power.cost)">
        
      </a>
</p>

And my stats array and function to set them:

$scope.cardPowers = [
{
  name: "balanced-low",
  attack: 800,
  defense: 800,
  cost: 2
},
{
  name: "balanced-medium",
  attack: 1500,
  defense: 1500,
  cost: 4
},
{
  name: "balanced-high",
  attack: 2500,
  defense: 2500,
  cost: 7
},
{
  name: "high-offense",
  attack: 2500,
  defense: 1000,
  cost: 5
},
{
  name: "base-offense",
  attack: 1500,
  defense: 1000,
  cost: 3
},
{
  name: "base-defense",
  attack: 1000,
  defense: 1500,
  cost: 3
},
{
  name: "high-offense",
  attack: 2200,
  defense: 1000,
  cost: 5
},
{
  name: "high-defense",
  attack: 1000,
  defense: 2500,
  cost: 4
},
{
  name: "high-offense-defense",
  attack: 2200,
  defense: 2500,
  cost: 6
}
];

$scope.cardStats = function(attack, defense, cost){
$scope.attack = attack;
$scope.defense = defense;
$scope.cost = cost;
};

*So in all I want to be able to create a few more values in the array to get a random set from when clicking on my what is essentially a "roll" stats button.