Personality traits and job performance. Refer to the Journal of Applied Psychology (January 2011) study of the relationship between task performance and conscientiousness, Exercise 12.54 (p. 750). Recall that the researchers used a quadratic model to relate y = task performance score (measured on a 30-point scale) to x1 = conscientiousness score (measured on a scale of -3 to +3). In addition, the researchers included job complexity in the model, where x2 = {1 if highly complex job, 0 if not}. The complete model took the form E1y2 = b0 + b1x1 + b21x12 2 + b3x2 + b4x1x2 + b51x12 2 x2

a. For jobs that are not highly complex, write the equation of the model for E1y2 as a function of x1. (Substitute x2 = 0 into the equation.)

b. Refer to part

a. What do each of the b’s represent in the model?

c. For highly complex jobs, write the equation of the model for E1y2 as a function of x1. (Substitute x2 = 1 into the equation.)

d. Refer to part

c. What do each of the b’s represent in the model?

e. Does the model support the researchers’ theory that the curvilinear relationship between task performance score 1y2 and conscientiousness score 1x12 depends on job complexity 1x22? Explain.