Power in statistical terms is the probability of rejecting a false null hypothesis. Power analysis, although generally not employed by biological anthropologists, is especially useful in interpreting statistical tests in which the null hypothesis is not rejected, and in determining appropriate sample sizes. In this report, the utility of statistical power analysis and the level of variation in power is illustrated by performing power analysis on paleopathology data (Cohen and Armelagos: Paleopathology at the Origins of Agriculture, 1984). The power analyses indicate that most samples are adequately large for detecting large differences among groups, but are inadequate for detecting small differences. Statistical analyses with inadequate power to detect small to medium effects may be of questionable utility in many areas of biological anthropology, as well as in paleopathology. The application of power analysis is recommended for determining necessary sample size in advance of data collection and for interpreting negative results.Statistical power analysis is a technique for determining the power of a statistical test. Power, in statistical terms, is the probability of rejecting a false null hypothesis. The purpose of the present paper is to draw the attention of anthropologists to the use of power analysis as a research tool by demonstrating its utility in paleopathology, one of several areas of anthropological research which routinely must consider statistical tests that fail to reject the null hypothesis, and the results from analyses with limited sample sizes.The neglect of statistical power analysis in the behavioral sciences was noted by Cohen (1962), specifically for psychology. Cohen found that in many studies the probability of rejecting a false null is inadequate and could be leading researchers to abandon fruitful areas of investigation. We believe that power analysis is also absent from most anthropological reports. Our survey (unpublished) of articles appearing in the American Journal of Physical Anthropology over the last five years suggests that the use of power analysis is still negligible in our field. Furthermore, a review of statistical textbooks often used by biological anthroDolomsts shows that Dower analysis, if discussed at all, is done so only briefly (e.g., Snedecor and Cochran, 1980; Sokal and Rohlf, 1981; Thomas, 1986).Commonly, statistical testing in biological anthropology places great emphasis on reducing the occurrence of type I error, i.e., the probability of rejecting a true null, with alpha set at an appropriately low level. Concerns regarding type I1 error are equally valid. Type I1 error occurs when a false null is not rejected, e.g., not differentiating between two fossil assemblages perhaps representing different lineages, or among different groups perhaps representing different degrees of acclimatization. The probability of committing a type 11 error in statistical testing can be estimated by a power analysis.Power analysis is very useful in the interpretation of resu...