Yeah I think I understood the intention. In that case it's a plot of conditional probability rather than probability density. I wouldn't change the article, it

Yeah I think I understood the intention. In that case it's a plot of conditional probability rather than probability density. I wouldn't change the article, it's clear enough and it's not like they're accurately plotted graphs, just sketches to get your idea across. Edit: By the way there is a distribution that describes something which is similar to a poisson distribution but with a changing rate, it is typically used for failure rate analysis (time before failure modelling) but could also be used here to describe time before bug discovery: http://en.wikipedia.org/wiki/Weibull_distribution http://en.wikipedia.org/wiki/Weibull_distribution