[EX02-115] Are airline flight arrivals ever on time? The general public thinks they are always late—but are they? The U.S. Bureau of Transportation Statistics keeps records and periodically reports the findings. Listed here are the percentages of on-time arrivals at the 31 major U.S. airports for the period January 1, 2004, to October 31, 2004.

ATL 73.55 BOS 78.38 BWI 80.91

••• Remainder of data on Student’s Suite CD-ROM Source: U.S. Department of Transportation, Bureau of Transportation Statistics

a. Draw a dotplot of on-time performance data.

b. Draw a stem-and-leaf display of these data.

c. Find the 5-number summary and draw a boxand-

whiskers display.

d. Find P10 and P20.

e. Describe the distribution of on-time percentage, being sure to include information learned in parts a through d.

f. Why would you be more likely to talk about the top 80% or 90% of the performance percentages than the middle 80% or 90%?

g. Are there airports whose on-time percentages appear to be quite different from the rest? How many? Which ones? Explain.