You can use the CONTRAST statement to perform custom hypothesis tests. If the hypothesis is testable in the univariate case, the Wald F statistic for is computed as
where is the contrast vector or matrix you specify, is the vector of regression parameters, , is the estimated covariance matrix of , rank() is the rank of , and is a matrix such that
has the same number of columns as
has full row rank
the rank of equals the rank of the matrix
all rows of are estimable functions
the Wald F statistic computed using the matrix is equivalent to the Wald F statistic computed by using the matrix with any row deleted that is a linear combination of previous rows
If is a full-rank matrix and all rows of are estimable functions, then is the same as . It is possible that matrix cannot be constructed for contrasts in a CONTRAST statement, in which case the contrasts are not testable.