Why doesn't my script work?

I'm trying to make this script play random music each time, But It Won't Work any Suggestions or ideas? What did I do wrong?

X = (math.random(1,5))
function onPlayerAdded(newPlayer)
if X == 1 then
    script.Parent.menu_sfx_audio.SoundId = "http://www.roblox.com/asset/?id=199768665"
    wait(.5)
    script.Parent.menu_sfx_audio:Play()
elseif X == 2 then
    script.Parent.menu_sfx_audio.SoundId = "http://www.roblox.com/asset/?id=199768665"
    wait(.5)
    script.Parent.menu_sfx_audio:Play()
elseif X == 3 then
    script.Parent.menu_sfx_audio.SoundId = "http://www.roblox.com/asset/?id=199768665"
    wait(.5)
    script.Parent.menu_sfx_audio:Play()
elseif X == 4 then
    script.Parent.menu_sfx_audio.SoundId = "http://www.roblox.com/asset/?id=167135038"
    wait(.5)
    script.Parent.menu_sfx_audio:Play()
elseif X == 5 then
    script.Parent.menu_sfx_audio.SoundId = "http://www.roblox.com/asset/?id=185601181"
    wait(.5)
    script.Parent.menu_sfx_audio:Play()
end
game.Players.PlayerAdded:connect(onPlayerAdded)