Measures of Central Tendency

Mean: arithmetic average of all scores in a distribution

Example:

   _       Σx      

                                                         X = -------       Σx = sum of all scores                                                        N          N = number of scores

13 + 14 + 15 + 16 + 17 = 75

Σx = 75                 N= 5

                  _         Σx         75

              X = ------- = -------   = 15

                          N           5

Median: the point at which exactly half of the scores in a distribution are below & half are above

1. Odd number          13, 15, 16, 17, 19

 2. Even number       12, 13, 15, 17, 18, 19 = 16

Mode: most frequently occurring score(s)

X	f
16 15 13 12 11 10 9 8	1 1 2 5 4 4 1 2