I), Xi⩾ 0. The objective function minimizes (or maximizes) a linear function of the decision variables, for example total cost or total energy content of the diet.

The correlation matrix from Kinzer and Kinzer (N=326) is used by Guttman (1957) as an example that yields an approximate simplex. McDonald (1980) uses this data set as an example of factor analysis ...

Ever wonder what sorts of errors freshman math students make? There are a couple of pretty basic ones.

A linear price scale is used on a chart that is plotted with real values spaced equidistant on the vertical axis.