The following functions allow you to analyze the properties of fractional factorial design matrices.
• fractruns(“gen”)—Returns the number of runs in a fractional factorial design matrix defined by the string of design generators “gen”.
• fractresol(“gen”)—Returns the resolution of a fractional factorial design matrix defined by the string of design generators “gen”.
• fractalias(“gen”, “fac”, [order])—Returns a matrix with all the aliased interactions for each factor and interaction specified in “fac”, based on the string of design generators “gen”. If order is specified, all the interactions up to that order are returned.
Arguments
• "gen" is a string specifying the design generators in a fractional factorial design, such as "A, B, C=AB, D=AC". The factor labels must be sorted in alphabetical order. For the separators, you can use a space, a comma, a colon, or a semicolon.
• “fac” is a string of factors and interactions, such as “A, B, AB, ABC”. For the separators, you can use a space, a comma, a colon, or a semicolon.
• order (optional) is an integer specifying the order of the interactions on which to report. order ≥ 1.