hi pab,
the standard deviation filter in expert lotto applies to the numbers of each individual ticket (standard deviation from the average value of the ticket numbers). the filter then allows to set minimum and maximum value of the standard deviation.
tickets like 1,2,3,4,5,6 or 43,44,45,46,47,49 have the lowest stdddev value, tickets like 1,2,3,47,48,49 have the highest stddev value.
the application also offers a table and a chart of standard deviations for the past winning numbers.