The amount of flow through a solenoid valve in an automobile

The amount of flow through a solenoid valve in an automobile\'s pollution-control system is an important characteristic. An experiment was carried out to study how flow rate depended on three factors: armature length, spring load, and bobbin depth. Four different levels (low, fair, moderate, and high) of each factor were chosen, and a single observation on flow was made for each combination of levels.

(a) The resulting data set consisted of how many observations?

Solution

There are 4^3 = 64 observations