spearman_brown {xxIRT}

Spearman Brown Prophecy

Description

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

Usage

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)