# Randomness is Random - Numberphile

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Regarding the bit near the end about how there is a possibility of about 1/4 that there are no streaks more than 3, and about 1/2 that it includes at most 1 streak of 4, I wonder if that helps...

Regarding the bit near the end about how there is a possibility of about 1/4 that there are no streaks more than 3, and about 1/2 that it includes at most 1 streak of 4, I wonder if that helps inform Simon on how to better predict Brady's guesses somehow, or is that just interesting information about true randomness.

1 vote
1. cfabbro (edited ) Link Parent
I think that was just to illustrate how most people are bad at understanding what random sequences really look like %-wise, since we tend to think small, and as a result of that we artificially...

I think that was just to illustrate how most people are bad at understanding what random sequences really look like %-wise, since we tend to think small, and as a result of that we artificially restrict ourselves when trying to design larger "random" sequences in our heads. But IMO what really helped Simon the most was not knowing any of that per se, but instead simply knowing some basic patterns that most people generally conform to when doing this "random" Heads/Tails game:

1. Most adults will typically only use a single streak of 3 at the longest (kids sometimes a streak of 4) in a sequence of 20

And so, given that Brady immediately started off with `HHH`, the next was a relatively safe \$20 bet on `T`.

1. After someone uses their single streak of 3 (or 4), the rest of the sequence will by necessity most likely be alternations between doubles and singles.

Which is how Simon was able to slowly accumulate wins throughout. Since Brady had already "used up" his streak of 3 right at the start, every time Simon saw a streak of `HH` or `TT` he knew the next was very likely going to be the opposite.

And finally, having seen Brady rigidly conform to those predictable patterns in 19 previous choices, and given Brady had picked `HH` directly before the final "flip", it was also a relatively safe \$100 bet on it ending with `T`.