Refer to the Journal of Personality and Social Psychology (Feb. 2012) study of on-the-job agreeableness and wages, Exercise 12.132 (p. 725). Recall that the researchers modeled mean income, E(y), as a function of both agreeableness score (x1) and a dummy variable for gender (x2 = 1 if male, 0 if female). The data was used to fit the model E(y) = β0 + β1x1 + β2(x1)2 + β3x2. A MINITAB normal probability plot of the residuals is displayed here. Interpret the graph. Does the random error term in the model appear to be normally distributed?

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Normal Probability Plot (response is Income) 99.9. 99 80 70- 60 - 50 40- 30 20- 10 0.1 -30000 -20000 -10000 10000 20000 30000 Residual Percent