Variation being somehow proportional to means is often a reality in biological data. Sample designs other than “two independent samples of the same size” are often necessary. This manual, based on a publication in the North American Journal of Fisheries Management, will guide you through those computational thickets, and show you how to use the accompanying (free download) Excel calculator.
This interactive Excel tool will calculate power (for a given design and sample size) or sample size (for given power and choice of design) for comparing two means. It accommodates unequal variability in a biologically realistic way, one- and two-tailed tests, and a variety of design options, including paired and independent samples. Power curves and other graphical tools will guide your reasoning.
Computations for Selection Ratios in a resource selection study are tedious and and be quite numerous. This interactive Excel tool gets rid of the tedium, and does numerous calculations quickly and easily, enabling you to think about the biology and the science instead of number-crunching. A fully functional version of this tool is available in the store.
