Abstract
Suppose a researcher wants to calculate the statistical power of an experiment comparing two parallel arms of behavioral interventions. Participants are randomized with equal probability into two intervention conditions. The experimenter wants to know the statistical power for a total sample size of 100 (50 in each intervention condition), assuming that the difference between the two sample means is half of the pooled standard deviation.
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Notes
- 1.
The code to plot Fig. 7.1 is available upon request. R makes it easy to plot the shaded areas under a curve. Basically, filled histograms such as the ones in Fig. 4.1 are used to produce the shaded areas under the curves. The Greek letters are added, for example, for the null distribution at m0 = 0 by mtext(bquote(delta[0] ==.(m0)), side = 1, at = m0, line=2, cex=2.0).
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© 2012 Springer Science+Business Media, LLC
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Li, Y., Baron, J. (2012). Statistical Power and Sample Size Considerations. In: Behavioral Research Data Analysis with R. Use R!. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-1238-0_7
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DOI: https://doi.org/10.1007/978-1-4614-1238-0_7
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Print ISBN: 978-1-4614-1237-3
Online ISBN: 978-1-4614-1238-0
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