Parameters and
are constants that can be empirically
determined. Based on the information in [3], we
assume
to be
and
to be
.
The Hick-Hyman Law can be useful only if the number of different
choices, , is known. Unfortunately, it is hard or even
impossible to estimate
for many cognitive processes. A menu
selection may actually involve more choices for a user than the
number of menu items because the user may evaluate the consequence
of selecting an item and the possible subsequent choices to decide
whether to select that item or not. In this study, we
conservatively assume
to be the number of most direct choices
like the number of menu items and the number of buttons to choose
from.