something to 1 so we can so many more rash you have to integrate now so we'll do is this a probability density function is defined saying that if you look at mass under the curve so the probability for X being an interval A to B is the integral from A to B of P of X DX for example if we think from zero here maybe till this point we could take the probability Mouse and that's then the in the area under the curve would be denoting how much parabola we associate with X landing in that interval so again we can't really talk about X stick on a