Procedure: • test variable (independent variable): • outcome variable (dependent variable): data: location name boundary type millions of years geologic events observed location one convergent 5 event 1 - himalayas 20 earth quakes event 2 - mountains location two divergent 5 event 1 - east africa 10 earth quakes 20 event 2 - volcanoes event 3 - ocean formation location three transform 5 event 1 - san andreas fault 10 earth quakes 20 event 2 - fault event 3 - mountains location four convergent 5 event 1 - aleutian islands 20 island chains event 2 - ocean formation location five divergent 5 event 1 - mid-atlantic ridge 10 earth quake 20 event 2 - volcanoes event 3 - seafloor spreading location six transform 5 event 1 - alpine fault 20 earthquake, volcanoes, fault event 2 - ocean formation, island chains