Question 139745: There is no answer associated with the question below posted but is showing as answered in the que. Please help!
Question 139208: 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
Noise Level Climb Cruise Descent Row Total
Low 6 2 6 14
Medium 18 3 8 29
High 1 3 14 18
Col Total 25 8 28 61
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! High level of cockpit noise in an aircraft can damage hearing of pilots who are exposed to this hazard for many hours. A Beoing 727 co-pilot collected 61 noise observations using a handled sound meter. Noise level is defined as "low (under 88 decibles), Medium (88 to 91), high (92 or more). There are three flight phases (Climb,Cruise,Descent). At alph=.05, is the cockpit noise level independent of flight phase?
State hypothesis
Ho: noise and flight phase are independent
Ha: they are dependent
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show degrees of freedom
(# of rows -1)(# of columns -1) = (2)(2) = 4
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find critical value of chisquare
Chi-Sq critical values for 2-tail Chi-Sq. Test: 0.484 and 11.143
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interpret p=value
p-value is 0.0044
Only 0.0044 of test results would show stronger evidence for rejecting Ho.
Since p-value is less than 5%, reject Ho.
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Noise Level,Climb,Cruise,Descent,Row Total
Low,6,2,6,14
Medium,18,3,8,29
High,1,3,14,18
Col total,25,8,28,61
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Cheers,
Stan H.
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