Example A: A person ate a ham sandwich and ran a race. She finished in first place.

Claim: The ham sandwich was the reason she won, and she should eat ham sandwiches before all her races.

Example B: A person ate different meals before 20 races that he ran. For ten races, he ate spaghetti before the race and finished in either first, second, or third place. For the other ten races, he ate fried chicken and finished in second place once, but finished in sixth or seventh place in the rest of the races.

Claim: Spaghetti helped his performance, and he should eat spaghetti before all his races.

Which claim is based on higher-quality evidence?