East Carolina University
Department of Psychology
Karl Wuensch's Statistical Help Page
Use of These Documents
Binomial Effect Size Display
Effect of n1/n2
on Estimated d and rpb
Notational Confusion for d and g Statistics
Odds Ratios -- why I prefer them over
Odds Ratios, Phi, and Base Rates -- phi can be greatly affected by base
rates, odds ratios are not.
Eigenvalues -- origin of the term
Exploratory Factor Analysis -- review of 1999 article by Fabrigar et al.
e-history -- base of the natural log
EX16-11 -- from Howell's fundamentals text, page 333
Analysis, Number of Factors, code for Parallel Analysis and Velicer's
-- many of these letters are used as statistical symbols.
Statistics -- useful links to Internet Resources, University of York
HOWL13-6 -- exercise 13-6 from the Fundamentals text
-- jokes involving statistics
Significant, Simple Main Effects Not -- suggestion on how to deal with
IV-DV -- Independent and Dependent
Kolgomorov, A. N. --
Mathematician whose work had an
enormous influence on statistics and other domains as well. His work
contributed to victory over the Japanese in the Pacific during World War II.
KR20 -- Kuder-Richardson 20
Kurtosis -- discussion of kurtosis
Likert -- what is a Likert scale and how do you
Logit -- pronunciations of the word
LESSONS -- these are my online lecture
notes for my stats classes
Low Power, Low Reliability -- Is it a big problem when results are significant?
Matrix CalculatorMediation and Moderation
Effects -- Jeremy Dawson
Moderation/Mediation Help Centre -- Paul Jose
Quantpsy.org -- Kristopher
Prevention Laboratory -- David MacKinnon
Mediation and Moderation Analysis -- Facebook Group
SAS Macros -- Yung-Jui Yang
SPSS and SAS
Macros, Andrew Hayes -- check out Process for SPSS and SAS
Meta-Analysis -- links to useful resources
Mindless Statistics -- Gigerenzer
Monty Hall Dilemma-- would you switch doors?
Assumptions -- Osborne, J., & Waters, E.
(2002). Four assumptions of multiple regression that researchers should
always test. Practical Assessment, Research & Evaluation, 8(2).
Multivariate Normality -- a few
links to get one started on this topic
NHST-SHIT -- Jack Cohen's wit and a list of
references on significance testing.
NHST-Quiz-- A little True-False quiz to test your
understanding of Statistical Hypothesis Inference Testing
Nonparametrics -- common misconception that nonparametrics have no assumptions
-- comparing your sample mean and variance to
that of a normative group
Normality Assumption -- EDSTAT-L
discussion on checking data for compliance with an assumption of normality
Ratios versus Probability Ratios
Omega-Squared -- advice on interpreting the omega-squared statistic
One-Tailed NHST -- does it ever make sense to test directional
OPSCAN -- using OPSCAN data sheets in your research
p Values -- The reign of p values is
p Values and the American Statistical Association
and the American Statistical Society
p-exact -- why researchers should report exact
p values suspiciously distributed -- something here smells like
-- Response by the American Statistical Society on p-values
Pairwise Comparisons -- discussion of pairwise/multiple comparisons procedures, including common misconceptions about them
Path-Matrix -- using matrix algebra to get effect coefficients in path analysis
r, Critical Values
Pitman's T -- testing variances with correlated samples
Poems -- Poems about statistics
-- An overview
by DaniŽl Lakens -- thorough overview for correlated and independent t
tests and ANOVA.
Probability of Replication -- is this new statistic
of any value?
Quotes about Statistics
-- The average human has one breast and one testicle.
R: Learning Statistics with R
Randomness -- what does it really mean when we
say an event is "random?"
Regression Towards the Mean
Reliability -- a few notes on reliability from Nunnally's text
Research Wahlberg --
Facebook page for stats/research geeks
Reversal-Paradox -- discussion of the reversal paradox,
also known as Simpson's paradox.
Sample Size Does NOT Affect the Probability
of a Type I Error
Sample Size Required, Finite
Population, Survey with Dichotomous Responses
SAS -- help using the SAS stat pack
Scales-Transform -- nonlinear data transformations
Signif-Testing -- why Frank Schmidt thinks significance testing the devil's work
Significant or Not?
Simpson -- Simpson's paradox, with bibliography
Skew -- location of mean, median, mode in skewed distributions
Split in Half --Splitting a data file into two
SPSS -- Help using the SPSS stats pack
SPSS2Excel2SAS -- write SPSS data to Excel and then bring into SAS
SS-Type -- different types of sums of squares
Standardized Confidence Intervals -- why not standardize confidence intervals
Statistician as Detective
Stepwise -- stepwise procedures are the devil's work
Student's t Statistic --
why "t" ?
Subjects -- What are Subjects?
t-CLT -- nonrobustness of the t statistic
t-Crit -- t approximated by z and some criticisms of significance testing
Transformations to Reduce Skewness
Type I Errors -- How frequent are Type I errors in the published literature?
Type-I-II-Errors -- Evaluating the Relative Seriousness of Type I versus Type II Errors in Classical Hypothesis Testing
Type III Errors -- Correctly rejecting the null but incorrectly inferring the direction of effect
Is .039 Larger or Smaller than .05?
Variance Inflation Factor -- Rules of Thumb
-- In addition to developing the Wald test used to test partial effects, he
contributed to the war effort (World War II) by discovering how better to
armor our bombers.
Why Standardize? -- when is it helpful to
standardize effect size estimates rather than presenting them in
- Proportions -- Pairwise
comparions for three or more independent proporotions
Return to Dr. Wuensch's Statistical Resources Page.
Contact Information for the Webmaster,
Dr. Karl L. Wuensch
This page most recently revised on 8-Sept-2021.