Question: High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. A Boeing 727 co-pilot collected 61 noise observations using a handheld sound meter. Noise level is defined as “Low” (under 88 decibels), “Medium” (88 to 91 decibels), or “High” (92 decibels or more). There are three flight phases (Climb, Cruise, Descent). Research question: At α = . 05, is the cockpit noise level independent of flight phase? (Data are from Capt. Robert E. Hartl, retired.)

Noise Level Climb Cruise Descent Row Total

Low

Medium

High

1 3 14 18 Col Total 25 8 28 61