cubic function

Creates cubic terms for Scheffe' full cubic model (3)

Creates cubic terms that are used by the function MixModel when fitting model (3)

cubic(a, b)

Arguments

• a: input - vector of mixture components in a column in the data frame
• b: input - another vector of mixture components in a column in the data frame

Returns

vector of elementwise a^2b-ab^2 function of terms in the a and b vectors

Author(s)

John Lawson