Table 9. Mann-Whitney tests of differences in doctors’ knowledge indices across seniority groups.

SENIORITY	Mean rank	Mann-Whitney U
Less than 5 years	65.3	U = 2085.5, p < .05
From 6 to 15 years	81.3
Less than 5 years	68.8	U = 2288.5, p < .05
From 16 to 25 years	85.9
Less than 5 years	78.0	U = 2836.0, p < .01
Over 26 years of seniority	100.0
From 6 to 15 years	95.2	U = 4439, p = .96
From 16 to 25 years	94.8
From 6 to 15 years	107.9	U = 5614.5, p = .9
Over 26 years of seniority	108.9
From 16 to 25 years	112.0	U = 6140.5, p = .84
Over 26 years of seniority	113.8