Cumulative Abnormal Returns Delta, United, and American Airlines announced , and October 7 (10/7). ely. Given the following information, calculate cumulative abnormal return an explanation. All of the 1. purchases of planes on July 18 (7/18), February 1- 2) (CAR) for these stoc. a group. Graph the result and prov stocks have a beta of 1, a o other announcements are made. Delta United American Market Company Market Comp Market Company 0 Date Return Return Date Return Return Date Return Return 7/12 3 i0/I 10/2 0/3 I.I 10/6 2/9 101.1 2/10 I.I 2/12 310/72.2 7/18 2.2 7/19-.9 7/20-1.0 10/8 0/9 10/103 10/13 2/15 I.I 2/165 7/24 2/18 3