This option assigns intervals in such a way that the middle interval breaks at the mean (or average) of the data values, and the intervals above and below the middle range are one standard deviation above or below the mean. Standard deviation is the square root of the variance.
Hii chaguo inateua vipindi katika namna ambayo katikati ya muda wa mapumziko katika maana (au wastani) ya maadili data, na vipindi juu na chini mbalimbali katikati ni moja kupotoka kiwango juu au chini ya maana. kupotoka kiwango ni mizizi ya mraba ya ugomvi.