I think the probability depends on the instrument. Trending instrument may have completely different picture. I am also unsure if it is recorded anywhere about this use case. There is a video by John Bollinger where he explains how he use Bollinger bands. That doesn’t talk about probability distribution at all.
Dicargo_Beam
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@HeWhoMustNotBeNamed, Oh, I thought that the mathematical expression of Bollinger Bands was derived from the normal distribution in that it was the same as the standardization of the normal distribution.