Confidence Intervals from Normalized Data: A correction to Cousineau (2005)

Presenting confidence intervals around means is a common method of expressing uncertainty in data. Loftus and Masson (1994) describe confidence intervals for means in within-subjects designs. These confidence intervals are based on the ANOVA mean squared error. Cousineau (2005) presents an alternati...

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Bibliographic Details
Main Author: Richard D. Morey
Format: Article
Language:English
Published: Université d'Ottawa 2008-09-01
Series:Tutorials in Quantitative Methods for Psychology
Subjects:
Online Access:http://www.tqmp.org/Content/vol04-2/p061/p061.pdf
Description
Summary:Presenting confidence intervals around means is a common method of expressing uncertainty in data. Loftus and Masson (1994) describe confidence intervals for means in within-subjects designs. These confidence intervals are based on the ANOVA mean squared error. Cousineau (2005) presents an alternative to the Loftus and Masson method, but his method produces confidence intervals that are smaller than those of Loftus and Masson. I show why this is the case and offer a simple correction that makes the expected size of Cousineau confidence intervals the same as that of Loftus and Masson confidence intervals.
ISSN:1913-4126