- What's the difference between BINOM.DIST with cumulative=TRUE versus FALSE?
- FALSE calculates P(X = number_s), the probability of exactly that count occurring. TRUE calculates P(X ≤ number_s), the cumulative probability of that count or fewer. For example, if checking 8 vehicles with FALSE, you get the probability of exactly 5 repairs; with TRUE, you get the probability of 0, 1, 2, 3, 4, or 5 repairs combined.
- Can I use BINOM.DIST for maintenance categories like 'no repair,' 'minor repair,' or 'major repair'?
- No. BINOM.DIST requires exactly two mutually exclusive outcomes per trial (success/failure, pass/fail, repair/no repair). If your fleet has three or more repair categories, use COUNTIFS to count each category separately, or consider a more complex statistical model.
- How do I choose the right probability_s value for my fleet data?
- Base it on historical rates from your maintenance log. If 140 out of 400 recent services resulted in repairs, set probability_s = 140/400 = 0.35. Alternatively, if you're testing a hypothesis (e.g., 'if my new maintenance schedule reduces repairs to 25%'), use that theoretical value directly as probability_s.
- Why does my BINOM.DIST formula return 0 or a very tiny number?
- Certain outcomes are mathematically very unlikely. If you request the probability of all 8 vehicles passing with only a 5% pass rate, the result is 0.05^8 ≈ 0.0000000039, which displays as 0 in standard cell formatting. Increase your cell's decimal places (right-click, Format Cells) to see the true value, or multiply by 10^8 to inspect it as an integer.