Set textFormat of dynamically created textField

here is the code:

// Create new textFormat object-----
var myTF:TextFormat = new TextFormat();
myTF.font = “Verdana”;
myTF.color = 0x333333;

// LOOP - create textfields, and name them.
for (var i:int = 1; i<6; i++){
var myText:TextField = new TextField;
myText.text = "text "+i;
myText.x = 25;
myText.y = 25+20*i;
myText.name = “t”+i;
addChild(myText);
trace(myText.name); //t1, t2, t3 etc.
}

// - event listener for the button to apply textformat when clicked
myBtn_btn.addEventListener(MouseEvent.CLICK, changeTextStyle);
function changeTextStyle(e:MouseEvent):void {
t3.setTextFormat(myTF); // - access of undefined property t3;
}

how do I address only the texField named t3 ?