An efficiency study was done on the delivery of first-class mail originating from the four cities listed in the following table. Recorded for each city was the average length of time (in days) that it took a letter to reach a destination in that same city. Samples were taken on two occasions, Sept. 1,2001 and Sept. 1, 2004.
|
City
|
Sept 1, 2001
|
Sept. 1, 2004
|
|
Wooster
|
1.8
|
1.7
|
|
Midland
|
2.0
|
2.0
|
|
Beaumont
|
22
|
2.5
|
|
Mara:bester
|
1.9
|
1.7
|