on positive values here and lambda is a choice that determines how quickly this thing decays versus maybe having a heavier tail you get some examples some samples from distribution three point one eight point two one point seven you can just say well what's the probability of each of these samples under this density multiply all of them together or take the log of the product of all of them and then see what maximizes it and in this case lambda is three over 13 and that might not have been as easy to read off by just looking at these numbers