Computes the effects in a factorial design at 2 levels.  The example problem is from Del Vecchio [1997, p 39]. (This 1.st ed.: 2003)

• Box, George E. P., William G. Hunter, J. Stuart Hunter, 1978, "Statistics for experimenters: an introduction to design, data analysis, and model building", John Wiley & Sons, Inc., New York, NY (USA).

• Del Vecchio, R. J., 1997, "Understanding design of experiments (a primer for technologists)", Hanser Publisher, Munich (Germany).

• Montgomery, Douglas C., 2001, "Design and analysis of experiments", 5.th ed., John Wiley & Sons, New York, NY (USA).

• 1829-11-10 Christoffel, Elwin Bruno (†1900-03-15)