The probelm with the above is that you would have to name each scene "scene1" or "scene2" and so forth. This is definitely a switch situation.
switch (Math.ceil(Math.random() * THE NUMBER OF SCENES YOU HAVE)) {
case 1:
gotoAndPlay("scenename",1);
break;
case 2:
gotoAndPlay("otherscene",1);
break;
case 3:
gotoAndPlay("goodscene",1);
break;
case 4:
gotoAndPlay("lastscene",1);
break;
//Keep inserting case statements just like the ones above until you reach the number of scenes you have, then finish with a close bracket.
}