In the article “ACL Reconstruction Using Bone-Patellar Tendon-Bone Press-Fit Fixation: 10-Year Clinical Results” in Knee Surgery, Sports Traumatology, Arthroscopy (2005, Vol. 13, pp. 248–255), the following causes for knee injuries were considered:

Activity                                               Percentage of Knee injuries

Contact sport…………………………………………………..46%

Noncontact sport………………………………………………44%

Activity of daily living………………………………………….9%

Riding motorcycle………………………………………………1%

(a) What is the probability that a knee injury resulted from a sport (contact or noncontact)?

(b) What is the probability that a knee injury resulted from an activity other than a sport?