Table 5 Relation between ?? and Pf.?? 1.0 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 -2 -2 -3 -4 -4Pf 0.16 0.081 0.036 0.014 0.47 10 0.14 10 0.34 10 0.72 10 0.13 10 0.21 10???5Reliability estimates are found to be sensitive to the distributions used for R and S.The failure probability should refer to a time interval, e.g. a year or the service life.