Problem $13-1$ Cumulative Abnormal Returns

Delta, United, and American Airlines announced purchases of planes on July $18(7/18),$ February $12(2/12),$ and October $7(10/7),$ respectively.

Delta

United

American

Date Market

Return Company

Return Date Market

Return Company

Return Date Market

Return Company

Return

$7/12\mathrm{.}37\mathrm{.}532/8\mathrm{.}861\mathrm{.}1210/1\mathrm{.}57\mathrm{.}24$

$7/13\mathrm{.}00\mathrm{.}272/9\mathrm{.}961\mathrm{.}1210/2\mathrm{.}47\mathrm{.}73$

$7/16\mathrm{.}79\mathrm{.}982/10\mathrm{.}47\mathrm{.}2810/31\mathrm{.}171\mathrm{.}17$

$7/17\mathrm{.}79\mathrm{.}642/11\mathrm{.}672\mathrm{.}4110/6\mathrm{.}171\mathrm{.}72$

$7/182\mathrm{.}161\mathrm{.}062/12\mathrm{.}37\mathrm{.}0410/72\mathrm{.}27\mathrm{.}45$

$7/19\mathrm{.}91\mathrm{.}592/151\mathrm{.}172\mathrm{.}1810/8\mathrm{.}57\mathrm{.}57$

$7/20\mathrm{.}961\mathrm{.}112/16\mathrm{.}57\mathrm{.}5710/9\mathrm{.}37\mathrm{.}22$

$7/23\mathrm{.}77\mathrm{.}442/17\mathrm{.}37\mathrm{.}2710/10\mathrm{.}37\mathrm{.}22$

$7/24\mathrm{.}27\mathrm{.}162/18\mathrm{.}37\mathrm{.}1410/13\mathrm{.}00\mathrm{.}17$

Given the above information, calculate the cumulative abnormal return $($CAR$)$ for these stocks as a group. $($A negative answer should be indicated by a minus sign. Leave no cells blank $$ be certain to enter $"0"$ wherever required. Do not round intermediate calculations and round your answers to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$