ADP                     How many people use my product
adp.t                   Calculates the predicted adoption probability
                        according to the triers' rate
adp.u                   Calculates the predicted adoption probability
                        according to the users' rate
ptriers                 Calculates the predicted prevalence of triers
                        according to the users' rate
pusers                  Calculates the predicted prevalence of users
                        according to the triers' rate
