Randomization algorithms in BASIC for experimental design.

Six BASIC programs for randomization of treatments with respect to space and time are presented. Program 1 is used to obtain randomization of several treatments in an equal number of positions for any number of replicates such that identical treatments are not replicated successively in the same position. Program 2 randomly assigns different treatments as specified in a grid of any size either (a) without constraints or (b) so that similar treatments do not occur next to each other either horizontally or vertically, or (c) horizontally, vertically, or diagonally. Program 3 assigns from five to 100 different treatments in equal proportions to a grid of specified size with treatments separated as in Program 2 (c) above. Program 4 randomly assigns any number of different treatments in equal proportions to a Latin square-like grid containing row and column cells with a multiple number of the treatments such that no identical treatments are replicated successively in the same row, column, or both row and column. Program 5 produces Latin squares of letters with unique numbered subscripts randomized. Program 6 makes Greco-Latin squares with an odd number of letters per side. These programs will aid in randomization of treatments within positions and replicates when a degree of uniformity or spacing of treatments is desired in order to increase the power of statistical tests. Examples of program output are discussed for tests with bark beetle pheromone components.