Example of Fractional Factorial
Juanito S. Chan, PIE
• A weed whacker is a grass trimmer that runs
on a mixture of gasoline and oil one-cylinder
• The weed whacker engine features a manual
starter (pull cord), and its performance is
largely a function of three controls: primer
pump, choke, and gas.
• Before starting the engine, you must first give
the primer several pumps, choke the air
intake, and pull the starter cord several times.
• To start the engine, the choke must be open.
Factors for weed-whacker experiment
Factor Name Low Level (−) High Level (+)
A Prime pumps 3 5
B Pulls at full choke 3 5
C Gas during full choke pulls 0 100%
D Final choke setting 0 50%
E Gas for start 0 100%