how do I make a spawner spawn different characters

I want to make 6 spawn points all that spawn a different character and i want the script to single out one of them at random so I can make him a target. Here’s what i got so far

using UnityEngine;
using System.Collections;

public class spawner : MonoBehaviour {

	public GameObject[] characters;
	public float spawnTime = 1f;            // How long between each spawn.
	public Vector3[] spawnPoints;         // An array of the spawn points this enemy can spawn from.
	public Transform trans;
	public int randomIndex;
	GameObject randomCharacter;

	void Start () {
		// Call the Spawn function after a delay of the spawnTime and then continue to call after the same amount of time.
		InvokeRepeating ("Spawn", spawnTime, spawnTime);
		trans = GetComponent <Transform> ();
		randomIndex = Random.Range (0, 14);
		randomCharacter = characters [randomIndex];
	}

	void Update (){

	}
	void Spawn ()
	{
		int spawnPointIndex = Random.Range (0, spawnPoints.Length);
		Instantiate (randomCharacter, spawnPoints[spawnPointIndex], trans.rotation);
	}
}

ummmm. ive never tried this but i think you can make a thing that calls out random numbers right? and then you say if (randomizer == 1){//spawn enemy type 1} and do that with 2 3 4 5 and 6

int num = Random.Range (number, otherNumber);