We propose a new application of the Friedman statistical test of significance to compare multiple retrieval methods. After measuring the average precision at the eleven standard levels of recall, our application of the Friedman test provides a global comparison of the methods. In some experiments this test provides additional and useful information to decide if methods are different.

It sometimes happens that the data collected are only in rank form within each block or normality cannot be assumed in the randomized block design. In these situations, a nonparametric approach called the Friedman rank test can be utilized. The Friedman rank test is primarily used to test whether c sample groups (i.e., the treatment levels) have been selected from populations having equal media...

Since Friedman's discovery5 in 1929 that urine from pregnant women would induce ovulation when injected into young female rabbits, there have been several attempts to use the test with various other mammals. These are summarized by Snyder and Wislocki8 and by Schultz and Snyder.7 Reports of experimental and clinical observations on the use of the Friedman test for diagnosis of pregnancy are ver...

The Authors Miriam Friedman Ben David is Professor of Medical Education, formerly Co-Director of the Clinical Skills Certification Programme at the Educational Commission for Foreign Medical Graduates (ECFMG) and Associate Dean at the Medical College of Pennsylvania, Philadelphia. Professor Friedman Ben David is currently at the Centre for Medical Education, Dundee, Scotland. Her main areas of ...

The Friedman (1939) test for pregnancy has the minor disadvantages that skill is required for the intravenous injection into the ear vein of the rabbit and that some 3 % (Albert, 1949; Evans and Krajian, 1944) of urine samples are toxic to the rabbit if injected intravenously. Ducey (1950) overcame some of these difficulties by injecting urine subcutaneously in doses of 20 to 30 ml. in the loos...