convert probability to z-score

Hi I made the a script is work out the valuse what they should do, but want to make tham in z-score as well can I get a help how to do it please.

Thanks

mu=21; %mean
s=7; %variance what is sqerroot 49
P=normpdf(X,mu,s);
plot(P)
%Probability calculation between 22 and 28 minutes.
PMin=normcdf(22,21,7);
PMax=normcdf(28,21,7);
Prob=PMax-PMin %Probability
%Calculating the probability in 30sec of the mean time.
ApMin=normcdf(20.5,21,7);
ApMax=normcdf(21.5,21,7);
Aprob=ApMax-ApMin

Answer 1

[Star Strider]

To calculate the z-score from a normal distribution probability, use the norminv (link) function.