Participants were asked to operate the three sets of functions
(Fig. 9b) in the same sequence used when operating the toolbar (to
scroll the wheel up and down once with the mouse cursor placed
on each tool ball). Each set of functions was executed once, and the
total time consumed was calculated to obtain the total time spent
on executing the three sets of functions (six software functions).
The times were measured twice and summed, exactly as with the
tool bar. Finally, the two totals were summed and the mean time
was calculated.