Supporting material that summarizes the characteristics of a complex set of numbers is referred to as

__________ political systems have been the most common throughout history

Fill in the blank with correct word

Given the following set of scores, what is the mean?

10, 17, 20, 17, 18, 15, 16, 18, 17 a. 16.44 b. 17.5 c. 17 d. 15