Power Analysis Case Study

When planning a study in Montana, I conducted a statistical power analysis (an important planning tool) to determine how much sampling effort needed to be expended at each site to detect an ecologically relevant amount of change. I based this analysis on some data from similar streams in the region.

The analysis found that if 3 samples were collected, that a 125% change in taxa richness (the number of species) was required before statistics could detect a "significant" difference. This means that all species would need to die--and not be replaced by tolerant organisms before the monitoring program could conclude that there was a "significant" change in the number of species.

Our Power Analysis tool helps ensure that ecological significance translates to statistical significance (and vise versa).