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Equation 11 · Part 1 · A Showdown Ladder Rating Measures the Ladder, Not the Player

Symbol E

EE
EE

What this part means

E is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

E is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

…founding decomposition: an observed score X on any single administration of a test equals a true score T — the score a person would get on average across infinitely many parallel administrations — plus measurement error E , so X = T + E , with E assumed to average to zero and to be uncorrelated with T across a population of test-takers [ 4 ] . From that single axiom the whole apparatus of reliability follows: reliability is the proportion of observed-score variance attributable to true-score variance, and the…

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