Studies: Bollinger Bands

Q:  Would you please let me know if there will be a standard deviation setting for Bollinger Bands?

A:  I am confused by the question. Standard Deviation is the basis of the Bollinger Bands in the first place.

Q:  I would like to set the average line to 21 bars and then be able to have the upper and lower bands .25 (.25 of one, standard deviation) above and below the average line.

A: 

Q:   Thank you for sending me the chart.  I was aware of the multiplier setting.  I also saw the following at Ensign Help "Multiplier - Used to adjust the distance of the Standard Deviation from the middle line.  An entry of 2 is recommended." However, someone told me that the multiplier was not based on standard deviation.  Is the multiplier based on standard deviation?

A:  The root of the channel is standard deviation.   The channel distance from the average line is:

upper band = average + stddev * multiplier
lower band = average - stddev * multiplier