# Exact Tests Data Considerations

**Data.** Calculating exact results can be computationally intensive, time-consuming,
and can sometimes exceed the memory limits of your machine. In general,
exact tests can be performed quickly with sample sizes of less than
30.

**Assumptions.** The asymptotic method assumes that the dataset is reasonably large,
and that tables are densely populated and well balanced. If the dataset
is small, or tables are sparse or unbalanced, the assumptions necessary
for the asymptotic method have not been met, and you should use either
the exact or the Monte Carlo method.

**Related procedures.** To set the random number seed so that you can duplicate results
using the Monte Carlo approximation, use Random Number Seed on the
Transform menu.