Can someone help me make the script?

I was trying to make a script that would respawn a Npc anytime you kill it but for some reason when I put the wait over 1 second the script doesn't work. So I was wondering if someone could make a respawning script for me?

Put this script in the NPC This should work:

name="Human"

robo=script.Parent:clone()

while true do
	wait(10)
	if script.Parent.Human.Health<1 then
		robot=robo:Clone()
		robot.Parent=script.Parent.Parent
		robot:MakeJoints()
		script.Parent:Remove()
	end
end

CHANGE/RENAME THE NPC'S HUMANOID TO HUMAN!