The penalty
In MECEE-BL, every wrong answer costs 0.25 marks. A blank costs nothing. So the question is: when is a guess worth it?
The expected-value rule
With 4 options and a pure random guess, your expected value is:
- Chance correct = 1/4 → +1 × 0.25 = +0.25
- Chance wrong = 3/4 → −0.25 × 0.75 = −0.1875
- Net expected value = +0.0625 per random guess.
So even a pure random guess is very slightly positive on average. But the real win comes from elimination:
| Options eliminated | Expected value per guess |
|---|---|
| 0 (pure random, 1 of 4) | +0.06 |
| 1 (1 of 3) | +0.42 |
| 2 (1 of 2) | +0.63 |
Practical rule
- If you can eliminate even one option, guess — the odds are strongly in your favour.
- If you have no idea at all, guessing is still marginally positive, but don't burn time on it during the exam.
- Never leave a question blank where you've narrowed it to two choices.
Bottom line: the 0.25 penalty is mild. Educated guessing is a scoring strategy, not a gamble.