A life test of 10 small motors with a newly designed insulat

A life test of 10 small motors with a newly designed insulator has been performed. The following data are obtained.   Please identify the distribution and characterize the reliability features, and estimate the reliability of (2000 hrs).

Failure time (hrs):    1200   1175      1450    1400    1580   2430   1870     2120   1930    2180   

Solution

Data : 1200, 1175, 1450, 1400, 1580, 2430, 1870, 2120, 1930, 2180

Standard Deviation : 434.97

Mean = 1733.5

z = (2000 - 1733.5) / (434.97/sqrt(10)) =1.94

Probability ( x>2000) = 1 - 0.9738 = 0.0262 Answer

P<0.05, Hence failed to reject null hypothesis