TRENDS is a program designed to carry out a power analysis of linear regression, particularly in the context of monitoring populations in wildlife studies. TRENDS summarizes the power analysis in 5 parameters: duration of study, rate of change, precision of estimates, alpha (type 1 error rate), and power (1-beta, where beta is the type 2 error rate). The value of any one of these can be estimated if the other 4 are specified.
