
151Fatigue Design of Lead-Free Electronics and Weibull Distribution
With the Weibull analysis software (using the MRR method) and by trial
and error, general equations for the relationships between ρ and β for differ-
ent sample sizes can be obtained.
For complete sample sizes, n, from 3 to 99, the relationship is represented
by
ρ=
β
−
+
e2.235939
n
0.546524
5.23201
(7.14)
For complete sample sizes, n, from 100 to 1,000, the relationship is repre-
sented by
ρ=
β
−
+
e2.241233
n
1.522754
58.32657
(7.15)
Equations (7.14) and (7.15) show that for a given sample size n, the approximate
relationship between ρ and β is a straight line passing through the ...