A Friedman test revealed a significant (p ¼ 0.000, c2
(5) ¼ 33.6)
effect of the device on rank. In the pair wise comparison of the
ranks by means of a Wilcoxon test the rank of the trackball differed
significantly from the ranks of each other device at a level of
p ¼ 0.001, and the mouse was ranked significantly worse than the
gamepad and the external touchpad at a level of at least p < 0.002.
However, there is a significant correlation (Sperman'sRho
¼ 0.224, df ¼ 178, two tailed, p ¼ 0.002) between rank and
expertise.