The Speedo LZR Racer Suit is a high-end, body-length swimsuit that was launched on February 13, 2008. When 17 world records fell at the December 2008 European Short Course Championships in Croatia, many believed a modification in the rules surrounding swimsuits was necessary. The FINA Congress, the international governing board for swimming, banned the LZR Racer and all other body-length swimsuits from competition effective January 2010. In a statement to the public, FINA defended its position with the following statement:
"FINA wishes to recall the main and core principle that swimming is a sport essentially based on the physical performance of the athlete" (BBC Sport, March 14, 2009).
Luke Johnson, a freelance journalist, wonders if the decision made by FINA has statistical backing. He conducts an experiment with the local university's Division I swim team. He times 10 of the swimmers swimming the 50-meter breaststroke in his/her bathing suit and then retests them while wearing the LZR Racer. A portion of the results are shown in the accompanying table.
In a report, use the sample information to:
1. Determine whether the LZR Racer significantly improves swimmers' times at the 5% significance level. Assume that the time difference is normally distributed.
2. Comment on whether the data appear to support FINA's decision.