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The FREQ Procedure |

**EXACT***statistic-options < / computation-options >***;**

The EXACT statement requests exact tests or confidence limits for the specified statistics. Optionally, PROC FREQ computes Monte Carlo estimates of the exact

Table 28.6 lists the available

**ALPHA=**-
specifies the confidence level for the confidence limits for the
Monte Carlo
*p*-value estimates. The value of the ALPHA= option must be between 0.0001 and 0.9999, and the default is 0.01. A confidence level of results in % confidence limits. The default of ALPHA=.01 results in 99% confidence limits. If is between 0 and 1 but is outside the range of 0.0001 to 0.9999, PROC FREQ uses the closest range endpoint. For example, if you specify ALPHA=0.000001, PROC FREQ uses 0.0001 to determine confidence limits. The ALPHA= option invokes the MC option. **MAXTIME=***value*-
specifies the maximum clock time (in seconds) that PROC FREQ can use
to compute an exact
*p*-value. If the procedure does not complete the computation within the specified time, the computation terminates. The value of the MAXTIME= option must be a positive number. The MAXTIME= option is valid for Monte Carlo estimation of exact*p*-values, as well as for direct exact*p*-value computation.

See the section "Computational Resources" for more information. **MC**-
requests Monte Carlo estimation of exact
*p*-values instead of direct exact*p*-value computation. Monte Carlo estimation can be useful for large problems that require a great amount of time and memory for exact computations but for which asymptotic approximations may not be sufficient. The MC option is available for all EXACT*statistic-options*except BINOMIAL, MCNEM, and OR. PROC FREQ computes only exact tests or confidence limits for those statistics.

The ALPHA=, N=, or SEED= option also invokes the MC option. **N=***n*-
specifies the number of samples for Monte Carlo estimation.
The value of the N= option must be a positive integer, and the default is
10000 samples. Larger values
of
*n*produce more precise estimates of exact*p*-values. Because larger values of*n*generate more samples, the computation time increases. The N= option invokes the MC option. **SEED=***number*-
specifies the initial seed for random number generation for
Monte Carlo estimation. The value of the SEED= option must be a positive
integer. If you do not specify the SEED= option, PROC FREQ uses the time
of day from the computer's clock to obtain the initial seed.
The SEED= option invokes the MC option.

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