Public variables

Can we change public or private variables.

package pGame.data
{
import flash.utils.*;

public class GameData extends Object
{
private var _timer:Timer;
private var _scores:Array;
public var currentLevel:Number = 1;
public var totalOpenedLevels:Number = 1;
public var levelData:Array;
If so then pls tell me how it can be done.

Yes. Read the Tutorials and FAQs