No. 247 · Evidence · Statistics and Probability
Null Hypothesis
Assume a claim does nothing until the evidence forces you to think otherwise.
In the Almanac
“The lady tasting tea”, 1935 · “Power Balance”, 2010–2011
Both stories in full, three ways to use it and where it misleads.
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Questions
What is Null Hypothesis?
The null hypothesis is the default assumption that a treatment, strategy or claim makes no difference. Instead of asking critics to disprove an idea, it makes the idea earn belief by producing results too surprising to be chance.
How do you use Null Hypothesis?
To use it, start skeptical of health products, workplace changes and investment claims. Compare against a fair baseline, and look for blinded or controlled tests. But remember that failing to find an effect is not proof there is none, since small tests can miss real effects.
When does Null Hypothesis matter?
Null Hypothesis is one of the 68 mental models for evidence, the situations where you ask: Is this really true? Within that, it belongs to “Testing a claim”, alongside False Negative, False Positive and Falsification.
What is an example of Null Hypothesis?
Two stories show it at work: The lady tasting tea (1935) and Power Balance (2010–2011). Both are told in full in The Mental Models Daily Almanac, which has two stories for each of its 365 models.
Which mental models are related to Null Hypothesis?
P-Values, Placebo Effect and Appeal to Authority. Null Hypothesis itself comes from statistics and probability.