The US Local Airport Keeps Track of the Percentage of Flights

Essay

The US local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals.The stem-and-leaf plot of the data for one year is below.
$\begin{array} { l l } 76 & 9 \\77 & 114 \\78 & \\79 & 07 \\80 & 88 \\81 & 2 \\82 & 1 \\83 & 88\end{array}$
Compute the standardized quartile value O_i for i = 4.