Problem $14-1$ Cumulative Abnormal Returns

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

$\backslash$table$[[$Date$,\backslash$table$[[$Delta$],[$Market$],[$Return$]],\backslash$table$[[$Company$],[$Return$]],$Date,$\backslash$table$[[$United$],[$Market$],[$Return$]],\backslash$table$[[$Company$],[$Return$]],$Date,$\backslash$table$[[$America$],[$Market$],[$Return$]],\backslash$table$[[$Company$],[$Return$]]],[\frac{7}{12},-\mathrm{.}43,-\mathrm{.}65,\frac{2}{8},-\mathrm{.}92,-1\mathrm{.}24,\frac{10}{1},\mathrm{.}63,\mathrm{.}39],[\frac{7}{13},\mathrm{.}00,\mathrm{.}33,\frac{2}{9},-1\mathrm{.}02,-1\mathrm{.}24,\frac{10}{2},\mathrm{.}53,\mathrm{.}71],[\frac{7}{16},1\mathrm{.}28,1\mathrm{.}59,\frac{2}{10},\mathrm{.}53,\mathrm{.}22,\frac{10}{3},1\mathrm{.}23,1\mathrm{.}23],[\frac{7}{17},-1\mathrm{.}28,-1\mathrm{.}08,2/11,\mathrm{.}73,3\mathrm{.}53,\frac{10}{6},\mathrm{.}23,-2\mathrm{.}77],[7/18,-2\mathrm{.}22,1\mathrm{.}12,\frac{2}{12},-\mathrm{.}43,-\mathrm{.}18,\frac{10}{7},-2\mathrm{.}33,-\mathrm{.}44],[\frac{7}{19},-\mathrm{.}86,-69,\frac{2}{15},1\mathrm{.}23,2\mathrm{.}91,\frac{10}{8},\mathrm{.}63,\mathrm{.}63],[\frac{7}{20},-\mathrm{.}92,-1\mathrm{.}16,\frac{2}{16},\mathrm{.}63,\mathrm{.}63,\frac{10}{9},-\mathrm{.}43,-\mathrm{.}19],[\frac{7}{23},\mathrm{.}74,\mathrm{.}52,\frac{2}{17},-\mathrm{.}43,-\mathrm{.}32,\frac{10}{10},\mathrm{.}43,-\mathrm{.}24],[\frac{7}{24},\mathrm{.}23,\mathrm{.}07,2/18,\mathrm{.}43,\mathrm{.}29,\frac{10}{13},\mathrm{.}00,-\mathrm{.}23]]$

Given the above information, calculate the cumulative abnormal return $($CAR$)$ for these stocks as a group. All of the stocks have a beta of $1$ and no other announcements are made. $($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$.,32\mathrm{.}16.)$