Question

2. Panama City Airways engine shop performs overhauls on the airline’s fleet of Pratt & Whitney JT8D engines. The average TBO for the fleet has been 5630 hours. 5 years ago the airline acquired 32 engines having “single crystal” high-pressure turbine blades. All of these engines have now made it through overhaul and the TBO for these “single crystal” engines was found to be 5426 hours with a standard deviation of 642 hours. Using a 1% significance level test the claim that the new type of turbine blades have reduced engine service life.

Answer 1

Given that :- X=5426 &=642 n = 32 id= 0.01 To test the hypothesis, Hoi u=5630 Hiiu < 5630 ( claim ) Test Statistics, o is unknown t = X - Y - 5426-5630 slun - 642/132 642 - - 204 113.49 -1.80 Degrees of freedom = n-1 331 P.Value = p [ +<-1.80), DF = 3 ) using t-table, - P-value = 0.0408 ✓ Here, P-value > 2=0.01, we fail to Reject Ho. There is not sufficient evidance to support the claims