Research Design and Statistical Consulting
George M. Diekhoff, Ph.D.

As time allows and the spirit moves me, I post things on this page that might be useful to those who, like me, are knee deep in dissertation statistics, DNP projects, and other quantitative research. Check in when the spirit moves you!

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Another Way of Spotting Low-Quality Survey Data: Identifying Flat-Liners and Random Responders

A variety of methods are available to help identify survey respondents who, for whatever reasons, have not provided thoughtful responses...
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Copy and Paste Large SPSS Tables and Figures Into Word Documents

Copy and Paste Large SPSS Tables and Figures Into Word Documents  Sometimes SPSS tables are so wide that when you...
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Your Case ID Numbers and SPSS’s Case ID Numbers Are Not the Same

It is helpful to number each case (line) in your SPSS data file so that you can refer to cases...
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The Values “k” and “c” in Tabachnick & Fidell’s Data Normalizing Transforms

In Tabachnick and Fidell's multiple editions of Using Multivariate Statistics, they offer formulas for performing square root, log10, and reciprocal...
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Another SPSS Caveat: SPSS Bar Graphs Depict “Valid Percents,” Not Actual Percents

When using the bar graphs that are generated by the Frequencies procedure in SPSS, if you've told SPSS to represent...
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Why a Dichotomously-Scored Nominal Scale Variable is Really a Ratio Scale Variable

Why is it that a dichotomously-scored (two-category) nominal scale variable can be used as a predictor in statistical procedures like...
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Normalizing Scores with a Data Transformation Doesn’t Change the Construct Being Measured

In the presence of skewed data distributions, one or another of the commonly used data transformations (square-root, log10, or reciprocal)...
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Using G*Power to Estimate Sample Size or Statistical Power for Partial and Semipartial Correlation

G* Power does not provide any direct application for estimating sample size requirements or statistical power for partial or semipartial...
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Using G*Power to Estimate Sample Size or Statistical Power for One-Way Within-Subjects (Repeated Measures) MANOVA

G* Power does not include an app to do power analysis for this very popular statistical procedure. It's misleading, because under G*Power's...
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