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The common "F test" for testing the equality of two population variances is very sensitive to the normality assumption, yet many introductory statistics books do not stress this sensitivity. Several alternative dispersion tests have been developed that do not assume normality, but these are rarely discussed other than in nonparametric statistics texts. Additionally, these tests generally require tables of critical values or software to calculate p values. We propose a simple graphical procedure, requiring no tables or software, that compares absolute deviations of one sample to another. With equal sample sizes, if one sample has the five largest absolute deviations, we conclude that its population has greater dispersion. We believe the simplicity of this test makes it a viable alternative to the often misleading F test and to other tests. [ABSTRACT FROM AUTHOR]

Fast mapping (FM) is a hypothetical, incidental learning process that allows rapid acquisition of new words. Using an implicit reaction time measure in a FM paradigm, Coutanche and Thompson-Schill (Coutanche, M. N., & Thompson-Schill, S. L. (2014). Fast mapping rapidly integrates information into existing memory networks. Journal of Experimental Psychology: General, 143(6), 2296–2303. ) showed evidence of lexical competition within 10 min of non-words being learned as names of unknown items, consistent with same-day lexicalisation. Here, Experiment 1 was a methodological replication (N = 28/group) that found no evidence of this RT competition effect. Instead, a post-hoc analysis suggested evidence of semantic priming. Experiment 2 (N = 60/group, online study, pre-registered on OSF) tested whether semantic priming remained when making the stimulus set fully counterbalanced. No evidence for either lexical competition nor semantic priming was detected. Experiment 3 (n = 64, online study, pre-registered on OSF) tested whether referent (a)typicality boosted lexical competition (Coutanche, M. N., & Koch, G. E. (2017). Variation across individuals and items determine learning outcomes from fast mapping. Neuropsychologia, 106, 187–193. ), but again no evidence of lexical competition was observed, and Bayes Factors for the data combined across all three experiments supported the hypothesis that there is no effect of lexical competition under FM conditions. These results, together with our previous work, question whether fast mapping exists in healthy adults, at least using this specific FM paradigm. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented acknowledging the readers interest on the article about the Count Five test published on the previous issue of the periodical.