What's another name for the average of a set of numbers?

Mean

Whose curiosity famously opened a box with dire consequences for humanity? What 1975 film involved a group of British knights seeking the Holy Grail? In "The Departed," who plays the mob boss Frank Costello? What animal does actor Chris Pratt famously train in "Jurassic World"? In chess, what is it called when you achieve victory in just two moves?