How to solve standard normal distribution function for unknown variable.

Dear Friends! i am having a problem of solving a function for unknown variable as given below; β = - Ф-1 (Pf) where Ф-1=is the inverse standard normal distribution function. The β values are known and i want to find out the values of Pf in matlab. Need help urgently. Thanks!

Answer 1

[Star Strider]

It seems that your ‘beta’ values are actually z-scores, since the standard normal distribution requires two parameters, those being the mean and standard deviation. For the z-score, those are taken to be 0 and 1, respectively, since the z-score normalizes them.

This could be what you want:

Pf = normcdf(beta)

or perhaps:

Pf = normcdf(-beta)

or using the core MATLAB erf function:

Phi = @(beta) (1- erf(beta/sqrt(2)))/2;
Pf = Phi(beta)
Pf = Phi(-beta)

Without more information, it is difficult to determine the exact solution to your problem. See the documentation on Find Cumulative Distribution Function of Normal Distribution (link). The argument to the erf function in that section would be your ‘beta’ values.

That is my best guess.

[Abdur Rasheed]

Sir thanks a lot..the second formula you've written has worked..[Pf=normcdf(-beta)] Thanks again

[Star Strider]

As always, my pleasure.

Answer 2

[Abdur Rasheed]

Dear Sir ! Hope you are okay. Sir,i have to plot double y plot in matlab and i want to edit both y-axis.I tried but one of the y-axis can be edited and not the other one.I need your help please. Please find the attached figure file here. Thanks!

[Star Strider]

I cannot work with your ‘.fig’ file. I cannot access the properties for the two different y-axes.