This was posted by a Facebook “friend” (who is among many on FB who seem to believe that figuratively hectoring like-minded friends on FB will instill caution among the incautious):
The point I want to make here isn’t about COVID-19, but about probability. It’s a point that I’ve made many times, but the image captures it perfectly. Here’s the point:
When an event has more than one possible outcome, a single trial cannot replicate the average outcome of a large number of trials (replications of the event).
It follows that the average outcome of a large number of trials — the probability of each possible outcome — cannot occur in a single trial.
It is therefore meaningless to ascribe a probability to any possible outcome of a single trial.
Suppose you’re offered a jelly bean from a bag of 100 jelly bean, and are told that two of the jelly beans contain a potentially fatal poison. Do you believe that you have only a 2-percent chance of being poisoned, and would you bet accordingly? Or do you believe, correctly, that you might choose a poisoned jelly bean, and that the “probability” of choosing a poisoned one is meaningless and irrelevant if you want to be certain of surviving the trial at hand (choosing a jelly bean or declining the offer). That is, would you bet (your life) against choosing a poisoned jelly bean?
I have argued (futilely) with several otherwise smart persons who would insist on the 2-percent interpretation. But I doubt (and hope) that any of them would bet accordingly and then choose a jelly bean from a bag of 100 that contains even a single poisoned one, let alone two. Talk is cheap; actions speak louder than words.