Final answer:
The sample size (n) should be large enough to guarantee accurate Simpson's rule approximation.
Step-by-step explanation:
In order to guarantee that the Simpson's rule approximation is accurate, the sample size (n) should be large enough. The size of n required depends on the original population from which the samples are drawn, and it should be at least 30 or the data should come from a normal distribution. If the original population is far from normal, then more observations are needed for the sample means or sums to be normal.