Spawning enemies at an offset

I have fixed spawn locations in my game and I would like to spawn my enemies within a range close to the spawn point, rather then the enemies coming straight from the one fixed point if you get me.

Is there a way I can do that with my current setup?

using UnityEngine;
using System.Collections;

public class spawnBall : MonoBehaviour 
{
	//The spawn points for the enemies
	Vector3[] spawnPoints;

	//Initialises the end of the array for the enemies
	int endOfArray;

	//The wait time before the coroutine will start
	private int timeToBegin = 2;
	
	//Determines the spawn time of the enemies
	private float spawnTime = 2;
	
	//The object spawned towards the enemy
	public GameObject[] randomBall;

	void Start()
	{

		//Finds all ovjects marked with the tag Spawn Points
		GameObject[] objs = GameObject.FindGameObjectsWithTag("SpawnPoints") as GameObject[] ;
		
		//Sets the spawnPoints varibale to the size of the objs array
		spawnPoints = new Vector3[objs.Length] ;
		
		//for loop which trasfers all data into the array
		for(int i = 0 ; i < objs.Length ; i++)
		{
			spawnPoints _= objs*.transform.position ;*_

* }*
* //sets the end point for the array*
* endOfArray = spawnPoints.Length;*

* //Starts the coroutines for the enemies and missiles*
* StartCoroutine(Spawn());*

* }*

* // Update is called once per frame*
* void Update () {*

* }*

* //Instantiates a new enemy based on a time given by the players score*
* IEnumerator Spawn()*
* {*

* yield return new WaitForSeconds(timeToBegin);*
* while (true)*
* {*
* int prefeb_num = Random.Range(0,15);
_
//I’d like to create the offset here on the x-axis*_
* Instantiate(randomBall[prefeb_num], spawnPoints[Random.Range(0,endOfArray)], Quaternion.identity);
_
yield return new WaitForSeconds(spawnTime);_
_
}_
_
}*_

* void OnGUI()*
* {*
* GUI.Label(new Rect(10, 10, 100, 100), "FPS: " + (int)(1.0f / Time.smoothDeltaTime));*
* }*

}

You can do something like this :

Float maxDistance = 15f;
Vector3 spawnpoint = spawnPoints[Random.Range(0,10)];
Vector3 target_pos = spawnpoint + new Vector3(Random.Range(0,maxDistance), Random.Range(0,maxDistance),Random.Range(0,maxDistance));
Instantiate(prefab, target_pos, prefab.transform.rotation);

You can of course change the range to negative, or make Y zero so they don’t spawn in the air.