rProphecy 2.0

Calculate the Spearman-Brown 'Prophecy' formula on your Mac.
2.0 (See all)

rProphecy is a standalone Mac program that calculates the Spearman-Brown 'Prophecy' formula that estimates the reliability of a test if its number of items is altered. You can calculate the modified test reliability by entering the current test reliability and the proportion of change. Alternatively, you can calculate the proportion of change needed by entering the current and modified test reliability.

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