A sample of a population should be large enough to:

The answer is; to reduce statistical error and ensure a real representation the entire population.

The size of the sample size determines the precision or confidence level of the applied statistics. A proper sample size is able to capture the variability and uncertainties of the larger population and therefore estimate the larger population with good confidence levels.

Answer: Span the full spectrum of a population's genetic variation.

Explanation: APEX 8/21/19