Stochastic logistic process: Time to extinction

SetDirectory["/Users/takasu/home/情報科学科の仕事/講義/平成２３年度/H23 大学院講義/Logistic growth model/logistic_models/build/Development/"]

data = ReadList["data-time_extinction",Real];
Length[data]
Min[data]
Max[data]

Mean[data]

Histogram[data]

para = {b1->0.2, b2->0, d1->0, d2->0.02}

carryingCapacity = (b1 - b2)/(d1 + d2)

carryingCapacity/.para

timeToExtinction = d2/b1/b1 Exp[b1/d2]

timeToExtinction/.para

{carryingCapacity,timeToExtinction}/.{b1->0.2, b2->0,d1->0,d2->0.01}

{carryingCapacity,timeToExtinction}/.{b1->0.2, b2->0,d1->0,d2->0.002}