Characteristics:

               1. A bell-shape or symmetrical distribution: mean = mode = median
 
            2. Completely determined by the mean, m and standard deviation, s
 
            3.  (i)  about 68% of data are  between m - s and m + s
                (ii)  about  95% of data are between x - 2s and m + 2s
                (iii) about 99.7% of data are between m - 3s and m + 3s

            4. Outliers are data outside of m - 3s and m + 3s