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“Many of the conceptual difficulties that people have with NHST have their roots, I believe, in a failure to distinguish between absolute and conditional probabilities and, in particular, in failure to understand that the value of p produced by conventional tests of statistical significance is a conditional probability—the probability of getting the obtained statistical result on the assumption that the null is true” (Nickerson, 2000, p. 262) [1]

This article has a lot of misconceptions, especially regarding p-values

p-values are difficult to interpret because they are:

  • Conditional probabilities: p = P (Data Results | H0 = True)
    • And they are often incorrectly understood to be P (H0 = True | Data Results)
  • Influenced by:
    • sample size
    • effect size

Making decisions in the face of uncertainty. Uncertainty = sampling error.

Any decision based upon a hypothesis test can possibly be incorrect (Type I or Type II Error). Replication is the ultimate way to deal with sampling error. “No matter how intriguing a result from a single study, it must be replicated before it can be taken seriously.” [2] And statistical tests end up being unnecessary with enough replication. (All of this is Kline).

This has occurred, even though, as Steiger (1990) expressed: ‘An ounce of replication is worth a ton of inferential statistics’ (p. 176).

 

 

 


  1. Nickerson, R. S. (2000). Null hypothesis significance testing: a review of an old and continuing controversy. Psychological Methods, 5(2), 241-301.
  2. Kline, R. B. (2013). Beyond significance testing: Statistics reform in the behavioral sciences. American Psychological Association.

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Introduction to Statistics and Statistical Thinking Copyright © 2022 by Eric Haas is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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