AppliedMultiple choice
A researcher checks each new idea against the same held-out period and keeps the ones that work there. What has happened to the holdout?
- ANothing; data held out from fitting stays out of sample however often it is used
- BIt has become in-sample
- CIt has become more reliable, because it has been tested against more ideas
- DIt is still valid as long as no model parameters were estimated on it
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