TYPES OF NUMERICAL DISTRIBUTIONS

  I.  Characterizing numerical distributions.
        A.  Unimodal and multi-modal distributions.
        B.  Symmetrical and skewed distributions.
        C.  Bell curves.

 II.  Normal distributions.
        A.  Characteristics.
              1.  Unimodal
              2.  Symmetrical.
              3.  Bell-shaped.
        B.  The Empirical Rule.
              1.  68% of all observations fall within one standard deviation 
                  of the mean. 
              2.  95% fall within two standard deviations of the mean. 
              3.  99% fall within three standard deviations of the mean. 

III.  The standard normal distributions. 
        A.  Standardizing a normal distribution. 
              1.  While all normal distributions are similar in shape, they 
                  can have different means and standard deviations. 
              2.  However, every normal distribution can be converted to a 
                  standard normal distribution. 
                    a.  Converting raw scores to z-scores (standard deviation 
                        units). 
                    b.  Interpreting z-scores. 
        B.  Characteristics of the standard normal distribution. 
              1.  Unimodal.  
              2.  Symmetrical. 
              3.  Bell-shaped. 
              4.  Empirical Rule applies. 
              5.  Mean of 0 and standard deviation of 1. 
        C.  The standard normal table. 
              1.  What is the standard normal table? 
              2.  Reading the standard normal table. 
              3.  Proportion of a distribution above, below, and between 
                  scores. 
              4.  Areas under the curve as probabilities.