4.18 In a vibration study, a random sample of 15 airplane components were subjected to server vibrations until they showed structural failures. The data given are failure times in minutes. Test the null hypothesis that these observations can be regarded as sample from the exponential population with density function f (x) ¼ ex=10=10 for x  0.

1.6, 10.3, 3.5, 13.5, 18.4, 7.7, 24.3, 10.7, 8.4, 4.9, 7.9, 12.0, 16.2, 6.8, 14.7