$2 = S = This standard deviation value provides significant information about the distribution of data around the mean. (a) The mean + one sample standard deviation contains approximately 68% of the measurements in the data series. (b) The mean + two sample standard deviations contains approximately 95% of the measurements in the data series. In Happyville, the corresponding dates for fall frosts + one and two standard deviations from the mean are : Minus two standard deviations: Minus one standard deviation:_ Plus one standard deviation: Plus two standard deviations: What would the probability of frost for the Julian days that you calculated above? Minus two standard deviations (Oct 2) Minus one standard deviation (Oct 15) At zero standard deviation (Oct 27) Plus one standard deviation (Nov 8) Plus two standard deviations (Nov 20) 32