Values can range from 0.00 to 1.00 (sometimes expressed as 0 to 100), with high values indicating that the examination is likely to correlate with alternate forms (a desirable characteristic). The KR-20 may be affected by difficulty of the test, the spread in scores and the length of the examination.

In the case when scores are not tau-equivalent (for example when there is not homogeneous but rather examination items of increasing difficulty) then the KR-20 is an indication of the lower bound of internal consistency (reliability).

The formula for KR-20 for a test with *K* test items numbered *i*=1 to *K* is

where *p _{i}* is the proportion of correct responses to test item

*q _{i}* = 1), and the variance for the denominator is

where *n* is the total sample size.

If it is important to use unbiased operators then the sum of squares should be divided by degrees of freedom (*n* − 1) and the probabilities are multiplied by

This page was last edited on 5 March 2018, at 15:50.

Reference: https://en.wikipedia.org/wiki/Kuder-Richardson_Formula_20 under CC BY-SA license.

Reference: https://en.wikipedia.org/wiki/Kuder-Richardson_Formula_20 under CC BY-SA license.

- 1950s
- Kuder-Richardson Formula 20
- 20th Century
- Special:GlobalUsageTW PHW29.svg
- Sutton%E2%80%93Taylor Feud
- 2nd Millennium
- Tetris
- Perlat Musta
- Anno Domini
- Apr%C3%A8s
- Common Era
- Chatti
- Leap Year Starting On Sunday
- Valgius Rufus
- List Of Permanent Representatives Of New Zealand To The United Nations In Geneva
- Lingbi County
- William K. Dickey
- Tunisian Constituent Assembly Election, 2011
- MOS:DISAMBIG
- Zine El Abidine Ben Ali
- Tunisian Revolution
- Habib Bourguiba
- Maritime Border
- Gilla Patr%C3%A1ic Mac Donnchada
- F A Cup
- French Conquest Of Tunisia
- Special:Contributions192.33.240.95
- En.wikipedia.orgJos%C3%A9 Amalfitani
- Ottoman Empire
- Tert-butylthiol