Conversion MTBF to R(t)
 
 Number of test specimen n -
 Test duration T hr
 Number of failures r -
 
 MTBF = nĚT/r hr
 Failure rate λ = 1/MTBF %
 R(MTBF) = exp(-λt) -
 R(0.5MTBF) -
 t(R=0.95)/MTBF -
Mean Time Between Failure (MTBF) of Hard Disk Drives
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