Participants were randomly assigned to read a short story printed in either 12-point font or 14-point font in one of three font style conditions: Courier, Times Roman or Ariel. Afterwards they answered several questions designed to measure memory recall. Number of independent variables :
Number of experimental conditions:
Number of possible main effects:
Number of possible interactions

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.