OPEN-SOURCE SCRIPT
Is the Bollinger Bands assumption wrong?

Bollinger Bands are the result of the assumption that closing prices will follow a normal distribution.
However, when I actually calculated the probability, the closing price does not follow a normal distribution.
According to the normal distribution, the probability that Z > 2 should be 2.2%, but on the chart, the probability is 6~9%.
Can we get a useful value for Bollinger Bands that we can use in our strategy?
We can measure volatility, but can we judge volatility based on a fixed value?
To the right of each Bollinger band value, the probability that the price is above the band is displayed.
The script is simply annotated with how each probability is calculated.
However, when I actually calculated the probability, the closing price does not follow a normal distribution.
According to the normal distribution, the probability that Z > 2 should be 2.2%, but on the chart, the probability is 6~9%.
Can we get a useful value for Bollinger Bands that we can use in our strategy?
We can measure volatility, but can we judge volatility based on a fixed value?
To the right of each Bollinger band value, the probability that the price is above the band is displayed.
The script is simply annotated with how each probability is calculated.
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
For quick access on a chart, add this script to your favorites — learn more here.
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
For quick access on a chart, add this script to your favorites — learn more here.
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.