Questions / Quant research, Probability & inference
Many null tests
You run 100 valid tests, all under true null hypotheses, each at a 5% significance level. What is the expected number of false rejections?
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Answer: 5 false rejections
- Linearity of expectation gives 100 × 0.05 = 5. Independence is not required for this expectation.
Interview shortcut. Linearity: 100 × 0.05, with no independence needed.
In the app this has a follow-up where one thing about the setup changes. Try the follow-up.