Kevin did not know whether the locker room was located down the short hallway to his right or down the long hallway to his left. Crossing his fingers, he decided to try the short hallway. His problem-strategy best illustrates

The answer is trial and error.

Explanation:

Trial and error is a decision-making and problem-solving method, often considered a heuristic or "mental shortcut", that involves making arbitrary choices or attempts until success is achieved.

It's possible that the person will learn from any mistakes in order to create a perfected method. This is especially common in natural sciences.  

answer; genetics;