The experiment is a within-subject counterbalanced design with the
twelve subjects in four groups (( 
)
of 3 subjects. Since all four permutations are included, statistical
results are presented for aggregated groups. Multiple One-way ANOVA
tests are used to compare user performance at the 0.05 level of
statistical significance. To investigate interface ordering effects
and question set differences three-way ANOVA (Interface Order, Task
Set, Interface Type) statistics are used.