Flight Costs Every Year Educational Services (ETS) Selects Readers for the Advanced

Essay

Flight costs Every year Educational Services (ETS) selects readers for the Advanced
Placement Exams. Recently the AP Statistics exam has been graded in Lincoln, Nebraska.
One objective of ETS is to achieve equity in grading by inviting teachers to be readers from
all parts of the nation. However budgets are a consideration also. The accountants at ETS
wonder if the flights from cities west of Lincoln are the same as flight costs from cities east
of Lincoln. A random sample of the expense vouchers from last year was reviewed for the
cost of airline tickets. Costs (in dollars) are shown in the table. $$\begin{array} { | c | c | } \hline \text { East } & \text { West } \\\hline 265 & 257 \\\hline 298 & 320 \\\hline 340 & 295 \\\hline 219 & 288 \\\hline 199 & 366 \\\hline 398 & 275 \\\hline 359 & 430 \\\hline 309 & 397 \\\hline 105 & 253 \\\hline 253 & 366 \\\hline\end{array}$$
Indicate what inference procedure you would use to see if there is a significant difference
in the costs of airline flights between the west and east coasts to Lincoln, Nebraska, then
decide if it is okay to actually perform that inference procedure. (Check the appropriate
assumptions and conditions and indicate whether you could or could not proceed. You do
not have to do the actual test.)