What function in MATLAB for calculating the value of inverse standard normal distribution function?

Dear all,

As you known, the probability of failure is expressed by Pf = 1 - F(beta), in which F is inverse cumulative probability distribution function of standard normal distribution. I have known the reliability index Beta = 1.81, but I can not find the function of F in MATLAB (I only found function of norminv() or erfcinv() but these functions is incrrect in this case.

Please help me to find out the appropriate function in MATLAB,

Thank you so much for your help.

Khanh

Answer 1

[Torsten]

Pf = normcdf(-beta);

[Khanh Dang]

It is correct function that I am looking for. Thank you so much, Torsten

Answer 2

[Bruno Luong]

There is no sense to substract 1 to *inverse* CPF, which take argument value in (0,1) and maps to (-Inf,Inf). It only makes sense of F is direct CDF, which take input value in (-Inf,Inf) and map it to (0,1).

So your question/equation is wrong to start with.

F=@(x) (erf(x)+1)/2;
ezplot(F)

1-F(1.81)

ans = 0.0052

[Khanh Dang]

Thank you so much.