When size presents problems

When size really does matter.

published online Feb 8, 2007; J. Physiol. Michael R. Deschenes When size really does matter Physiology in Press This information is current as of January 29, 2008 http://jp.physoc.org/cgi/content/abstract/jphysiol.2007.128546v1 The latest version of this article is at: within 10 weeks. The Journal of Physiology Online normally appear in an issue of articles will Physiology in Press DOI. J Physi...

Problems When Interpreting Research Results Using Only P-value and Sample Size

The following three probabilities seem crucial when interpreting data, especially in the behavioral sciences:1) the probability that an effect is present in the population, 2) the probability that a replication is significant; and 3) the probability that the effect for a single individual in the population is in the expected direction. In our study, we asked 51 subjects (university students and...

THE MATHEMATICS COLLOQUIUM presents

Phase transitions are one of the most common phenomena, e.g., water and vapor in our daily life, or liquid crystal for a laptop. In the last few decades, extensive explorations have been made on stationary phase transitions, e.g. theory of renormalization group. In contrast, much less understanding is yet available for the dynamics, namely, the evolution of a system undergoing phase transitions...

When attachment disorder presents with symptoms of gender identity disorder: case discussion.

Some problems with sample size

When I began my career in medical statistics, back in 1972, little was heard of power calculations. In major journals, sample size often appeared to be whatever came to hand. For example, in that month, September 1972, the Lancet contained 31 research reports which used individual subject data, excluding case reports and animal studies. The median sample size was 33 (quartiles 12 and 85). In th...