## Significance and Effect Size: The p<.05 cliff

How did p<.05 become the magic cliff, before which everything is significant and beyond which nothing matters. Itβs not unusual for a finding to be …

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How did p<.05 become the magic cliff, before which everything is significant and beyond which nothing matters. Itβs not unusual for a finding to be …

A test of significance is used to determine whether an effect is likely to have occurred by chance. There has been much criticism of using …

Read moreSignificance and Effect Size: The Bonferroni Correction

In the early 1970s, Robert Rosenthal published a meta-analysis examining the effects of psychotherapy. About half of the studies found significant improvement in the mental …

For most people, effect size is a difficult concept to visualize. The most common form for reporting effect size is r (for correlation) or its …

The terminology generally used in reporting statistics is inherently confusing to most of us when we start out in conducting research. For example, it seems …

The following regression exercise measures the original relationship between unemployment and real output, as established first by the economist Arthur Okun in the 1960s.

Before talking about this technique, let’s clarify that when the name repeated measures MANOVA is used, it commonly refers to a repeated measures ANOVA in …

Read moreWhen do I need to use a repeated measures MANOVA and what data structure do I need?

Logistic regression models estimate the log odds of the outcome occurring vs the log odds of the outcome not occurring for a given independent variable …

Read moreLogistic regression vs. ordinal logistic regression: getting the interpretation right

One common problem researchers face when running a regression analysis is how to include categorical predictors. Unlike using continuous variables, which you can simply add with no previous manipulation, including categorical variables requires extra work when performing the analysis and interpreting the results.

Why do we need to know the data distribution to do our analyses? We need to know how the data are distributed to determine the …

ANOVA (Analysis of Variance) is a parametric statistical test. The one-way ANOVA procedure is used when the dependent variable is measured either on an interval …