statistical power
C2CEFR level
80/100Rarity: very rare
TechnicalRegister
The probability that a test will detect a real effect of a given size if one genuinely exists.
We ran a power analysis and needed 12,000 users per variant to reach 80% power.
Rarity runs from 0 (a word everyone knows) to 100 (almost never seen outside specialist or literary writing). Level is the word's real difficulty on the CEFR scale, from A1 to C2.
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