how to get mean residual life? (MRL)

I have a code for reliability.

clc; clear;

tt=200; b=10; sigma1=2; i=1;

for t = 1 : 1 : tt; mu=b*t; sigma=sigma1*t; P = normcdf(1000,mu,sigma); v(i)=P;

    i=i+1;

end

plot(v) title(' Probability of reliability'); xlabel('Time (months)'); ylabel('Reliability graph');

Now I need to get mean residual life according to this reliability.

Is there any matlab function that does this?