Ra. Charter, NOTE ON THE UNDERREPRESENTATION OF THE SPLIT-HALF RELIABILITY FORMULAFOR UNEQUAL STANDARD DEVIATIONS, Perceptual and motor skills, 82(2), 1996, pp. 401-402
The split-half reliability formula used when the standard deviations f
rom the test halves are unequal should be applied routinely instead of
the Spearman-Brown formula.