Power and Sample Size Estimation Techniques for Fisheries Management: Assessment and a New Computational Tool

Department of Statistics, University of Wyoming
Laramie, Wyoming
82071-3332, USA

Formulae for sample size calculations in the literature are often predicated on unrealistic assumptions (e.g. equal variances) or unrealistic, or simply undesirable, designs (two independent samples of the same size). In addition, sample size and power calculations usually involve repeated use of any given formula, as the researcher works through varying inputs (alpha, power choices, design choices, etcetera), making the process of considering sample size and power issues unpleasantly tedious and error-prone. I survey formulae currently in the fisheries literature, describing deficiencies. I then discuss sample size formulae that correct these deficiencies, and describe a freely available Excel tool that enables the calculations.