Question 188239
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
---------------
NOTE: It would be much easier to handle this if you posted the data
in a 4 by 4 rectangular format.
------------------------------------------
Ho: Row and column factors are independent
Ha: Row and column factors are dependent
----------
I ran a Chi-Sq Test on the 3 x 3 set of data and go the following:
--
test statistic: Chi-Sq = 15.1601
p-value: 0.0044
df = (3-1)(3-1)= 4
-----------------------------
Conclusion:
Since the p-value is less than alpha=5%, reject Ho.
The noise is dependent on the cruise configuration.
========================================================
Cheers,
Stan H.