By my math, if each participant faced 25 trials, and each participant has a 50% chance of success on each trial, then you'd expect 40 people to get a score of 2

By my math, if each participant faced 25 trials, and each participant has a 50% chance of success on each trial, then you'd expect 40 people to get a score of 20+ (80%) just due to chance. To give an idea.