P	failure probability
S	Maximum stress/MPa
N	number of fatigue cycles (life)
x	independent variable (number of failure cycles or a function of number of failure cycles)
α	position parameter (minimum life)
β	scale parameter (characteristic life)
γ	shape parameter (slope of the cumulative distribution function)
S 0	maximum stress correction parameter/MPa
N 0	life correction parameter
A	correction parameters
B	correction parameters
n	sample size
$N_i$	the fatigue failure cycle number corresponding to each maximum stress $S_i$
Si	Maximum stress
C	parameters related to the loading mode of experimental materials
m	parameters related to the loading mode of experimental materials
$\log N_p$	logarithmic fatigue life obeying the standard normal distribution
$\mu$	average logarithmic fatigue life
${\mu }_p$	standard normal skewness corresponding to the reliability P
$\sigma$	standard deviation of logarithmic fatigue life.