applications

Unequal inclusion probabilities

applications, simulation
travel time, stratification

The Sonoran Desert is among the most extreme environments on Earth. Sampling in these remote, rugged landscapes requires a different approach. When the Park Service established monitoring in Organ Pipe Cactus National Monument they used an approach to select sites based on the cost of travel to sites on the broader landscape, visiting less “costly” sites with higher probability than more costly sites. The cost surface that defined the probability of inclusion of sites was developed using terrain data, and a tool that estimates the time to travel to any arbitrary location on the landscape. ...

Interpreting coefficients

applications
inference

Making sense of the effects of variables included as predictors # Some aspects of covariate effects are readily apparent – for instance, the sign of a coefficient in a model says at least something about the general directionality of the effect, positive or negative. However, a deeper understanding of a model typically requires inferences that go well beyond simple measures of the directionality or significance of effects – it requires understanding the size of effects. ...