spearman_brown function

Spearman Brown Prophecy

Use Spearman-brown formula to compute the predicted reliability when the test length is extened to n-fold or reversely the n-fold extension of test length in order to reach the targeted reliability

spearman_brown(n, rho)

spearman_brown_reverse(rho, target)

Arguments

• n: extend the test length to n-fold
• rho: the reliability of current test
• target: the targeted reliability

Examples

spearman_brown(2, .70)
spearman_brown_reverse(.70, .85)