Math.Random Cutsom Value (Not So Random)?

So basically I want to make a game where each round a player is reassigned his team, but I want there to be 3x as many players on one team (They have the disadvantage). So I'm using math.random, but how would I make it so that It's still random, just the odds are in one teams favor? Here is the script:

while true do
	wait(5)
	teamchange = math.random(2)
	if teamchange == 2 then
		game.Players.LocalPlayer.TeamColor = BrickColor.new("Really red")
	end
	if teamchange == 1 then
		game.Players.LocalPlayer.TeamColor = BrickColor.new("Dark stone grey")
	end
end

Hope You Can Help, Thanks!