Statistical are the requirements that the population from which one is sampling has specific characteristics that will allow one to make accurate inferences.

Assumptions.

Explanation:

'Statistical assumptions' are demonstrated as the requirements that involve the population, from which samples are collected on the basis of possession of particular characteristics that allows deducing precise conclusions. The samples are selected from the population by carefully observing certain characteristics in them as they are representative of the entire population that helps in generating an accurate and reasonable deduction or data because an incorrect sampling may end up in wildly false and invalid conclusions. Therefore, 'assumptions' is the correct answer.

rain should be the answer.