The MULTTEST Procedure

Computational Resources

PROC MULTTEST keeps all of the data in memory to expedite resampling. A large portion of the memory requirement is thus 8*NOBS*NVAR bytes, where NOBS is the number of observations in the data set, and NVAR is the number of variables analyzed, including CLASS, FREQ, and STRATA variables.

If you specify PERMUTATION=number (for exact permutation distributions), then PROC MULTTEST requires additional memory. This requirement is approximately 4*NTEST*NSTRATA*CMAX*number*(number + 1) bytes, where NTEST is the number of contrasts, NSTRATA is the number of STRATA levels, and CMAX is the maximum contrast coefficient.

If you specify the FDRBOOT or FDRPERM option, then saving all the resamples in memory requires 8*NSAMPLE*NOBS bytes, where NSAMPLE is the number of resamples used.

The execution time is linear in the number of resamples; that is, 10,000 resamples will take 10 times longer than 1,000 resamples. The execution time is also linear in the sample size; that is, 100 resamples of size N will take 10 times longer than 100 resamples of size 10N.