var audio = ["audio-1.mp3", "audio-2.mp3", "audio-3.mp3", "audio-4.mp3", "audio-5.mp3"];

var $btn = $('button');

var $audio = $('audio');

​

function getRandomAudio() {

    var max = audio.length;

    return Math.floor(Math.random() * (max + 1));

}

​

$btn.on('mouseover', function(){

  var index = getRandomAudio();

  $audio.attr('src', audio[index]);

  $audio.get(0).play();

});