6 ms·
Statistics is simply working against you, system tests are a long chain of of (let's say) independent events with (let's hope) a small chance for failure. But y
by 2rsf 6y ago
Statistics is simply working against you, system tests are a long chain of of (let's say) independent events with (let's hope) a small chance for failure. But your test multiply those probabilities creating a much bigger probability for failure.
Now you run multiple tests, each with a more complex environment than your real system (you need to control your tests, test logs etc.) usually on a lesser environment than your production one. Add all this and you'll get an uncomfortable probability of failure
- abjKT26nO8 6y ago> But your test multiply those probabilities creating a much bigger probability for failure. Minor nitpick: when probabilities multiply, they get smaller. Such is the nature of numbers in the range [0, 1]. Multiplication would happen when counting the probability of two (independent) events coinciding. What you're thinking about here is the probability of any one of several events occuring. That will be a (rather convoluted) sum, not a product.
- 2rsf 6y agoWe engineers can do convoluted sums, the assumption is that the events are independent and you multiply the probability of success (or 1-probability of failure).