15 (1 point) Question 15 Saved Head injuries are fairly common among alpine skiers and snowboarders. For a recent study, results indicated that increased use (or frequent wearing) of a helmet while skiing was associated with a 60% reduction in injury. This means that: Question 15 options: 1) There is a causal link between helmet use and head injuries. 2) There is a likely indirect association between helmet use and head injuries. 3) There are enough variables to prove causation. 4) The