What is multiple testingWhat is multiple testing


Figure 1

Disease prevalence in a population: We compare the known population average of 4% to a test group in which 9/100 individuals have the disease.
Disease prevalence in a population: We compare the known population average of 4% to a test group in which 9/100 individuals have the disease.

Figure 2

A Scenario where 100 individuals get tested for a disease. The disease prevalence is 0.04. The experiment is repeated 200 times
A Scenario where 100 individuals get tested for a disease. The disease prevalence is 0.04. The experiment is repeated 200 times

Figure 3

What does the above code do:


Types of errors and error ratesTypes of errorsImplications of type I and type II errors


Figure 1

Confusion matrix
Confusion matrix

Figure 2

A tree diagram describing the outcomes of a breast cancer test
A tree diagram describing the outcomes of a breast cancer test

Figure 3

Which error rate should you control for?
Which error rate should you control for?

Family-wise error rate


Figure 1

Relationship between Overall Hypothesis and Individual Hypotheses (Effects of Air Pollution on Disease Prevalence)
Relationship between Overall Hypothesis and Individual Hypotheses (Effects of Air Pollution on Disease Prevalence)

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Figure 3

We see that the adjusted \(\alpha\) is dropping quickly. For \(20000\) tests, which is a reasonable number in genomic screens, alpha will be:


False discovery rateIntroductionThe theory of p-value HistogramsThe False Discovery RateWrap up


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Figure credit Cecile LeSueur
Figure credit Cecile LeSueur

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Figure 5

This cumulative distribution function answers the question “for a given value of \(|t|\), how many other elements of the simulation are smaller than this value?”. Which is exactly the opposite of what we’re asking when calculating a p-value. In fact, the p-value is defined as \(1-\text{CDF}(|t|)\), which looks like this:


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Figure 10

A p-value histogram decomposition (adapted from MSMB)
A p-value histogram decomposition (adapted from MSMB)

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Pairwise comparisonsPairwise comparisons


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SummaryError ratesA Cook book to navigate multiple testing effectively


References and Further ReadingBooksOnline Resources