The familywise Type I error rate is a familiar concept in hypothesis testing, whereas the per-family Type I error rate is rarely addressed. This article uses Monte Carlo simulations and graphics to make a case for the relevance of the per-family Type I error rate in research practice and pedagogy.
Simulations were conducted to evaluate the statistical power and Type I error control provided by several multiple-comparisons procedures in two-group designs. Stepwise Bonferroni-based procedures, which are known to control the familywise Type I error rate, tended to be more powerful than other methods but did not control the per-family Type I error rate (PFER). It is proposed that more attention should be given to the PFER, particularly with regard to these procedures. Only two methods controlled the PFER: the classical Bonferroni procedure and a modified version of MANOVA-protection. Which of these two procedures was more powerful depended on multiple factors that this article describes in detail and illustrates graphically. It is concluded that which multiple-comparisons procedure is preferable depends on the number of outcome variables, the importance of the PFER, the necessity of confidence intervals, and the extent to which significance in multiple variables is more valuable than significance in one variable.
Certain recorded drum breaks, i.e., drum patterns played without other instrumentation, have achieved iconic status, largely as a result of being frequently “sampled” in other recordings. Although these highly influential drum breaks (sometimes called breakbeats) have been integral to much of the hip-hop and other music produced in recent decades, there has been little scholarly investigation of their rhythmic features. To that end, this study examined 30 classic drum breaks from the “breakbeat canon,” focusing primarily on sixteenth-note swing (a systematic delay of even-numbered sixteenth-note divisions of the pulse). Such swing was common among the examined drum breaks, though the magnitude of swing was often fairly subtle (median swing ratio = 1.2:1). In contrast to some findings regarding jazz drumming, the magnitude of swing was uncorrelated with tempo, though the ranges of both variables were somewhat constrained. Backbeat delay (a systematic delay of snare drum at even-numbered beats) was found to be frequently present at beat 2, but not at beat 4. Additionally, this study introduces a quantity called “swing density,” defined as the proportion of even-numbered divisions (at the swing level) that contain events. The importance of this quantity to the perceptual effect of swing is discussed.
Fallacious arguments against multiplicity adjustment have been cited with increasing frequency to defend unadjusted tests. These arguments and their enduring impact are discussed in this paper.
Although color vision deficiency (CVD) is fairly common, it is often not adequately considered when data is presented in color graphics. This study found that CVD tends to be mentioned neither in the author guidelines of psychology journals nor in the standard publication manuals of the field (e.g., the publication manuals of the American Psychological Association and the American Medical Association). To illustrate the relevance of this problem, a panel of scholars with CVD was used to evaluate the color figures in three respected psychological science journals. Results suggested that a substantial proportion of those figures were needlessly confusing for viewers with CVD and could have been easily improved through simple adjustments. Based on prior literature and on feedback from the panelists, recommendations are made for improving the accessibility of graphics in psychology reports.
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