In this context, what does the author mean by "control?" Control means testing the effects of certain variables or lack of those variables on the overall equation or experiment.

5.4d. On page 609, the author begins and continues on subsequent pages explaining mediator effects. What are mediating variables? What is an analysis using mediating variables?

In a given research study, a mediating variable is a factor that is presumed to form or act as an intervening link between two or more variables that have been determined to be causally connected (Baron & Kenney,1986)

5.4e. On page 614, the author begins and continues on subsequent pages explaining moderator effects. What are moderating variables? What is an analysis using moderating variables?

A moderating variable is noted to represent a factor or variable that effectively alters the effect of an independent variable X on another dependent variable Y.

References

Baron, R.M. And Kenny,...

(1986) "The Moderator-Mediator Variable Distinction in Social Psychological Research -- Conceptual, Strategic, and Statistical Considerations," Journal of Personality and Social Psychology, Vol. 51(6), pp. 1173 -- 1182.
Bello, Daniel & Williamson, Nicholas (1985, Fall). The American Export Trading Company: Designing a New International Marketing Institution. Journal of Marketing, 49(4). 60-69.

Hise, Richard T; Gable, Myron; Kelly, J. Patrick; and McDonald, James B (1983, Summer). Factors Affecting the Performance of Individual Chain Store Units: An Empirical Analysis. Journal of Retailing, 59(2). 22-39

Koch, G.G. And Tangen, C.M. [1999]. Nonparametric analysis of covariance and its role in noninferiority clinical trials. Drug Information Journal

Tharenou, Phyllis (2001, December). The relationship of training motivation to participation in training and development, Journal of Occupational and Organizational Psychology. 74 (5). 599-622.