function ztest not found in R2015a

Dear all,

when searching for ztest in R2015a I cannot find it. Does anyone know how can I add it? I did the same for ttest getting the same issue.

Regards,

Gilly

Answer 1

[Star Strider]

You have to have the Statistics and Machine Learning Toolbox.

The core MATLAB functions erfc and erfcinv can emulate the normal probability distributions:

P = @(z) erfc(-z/sqrt(2))/2;                  % Equivalent to ‘normcdf’
CV = @(alpha) -sqrt(2) * erfcinv(2*alpha);    % Equivalent to ‘norminv’

and the t-distribution is a one-line anonymous function:

tdist2T = @(t,v) (1-betainc(v/(v+t^2),v/2,0.5));    % 2-tailed t-distribution
tdist1T = @(t,v) 1-(1-tdist2T(t,v))/2;              % 1-tailed t-distribution

where ‘t’ is the t-statistic and ‘v’ the degrees-of-freedom.

[Guilherme Barbosa]

Thanks a lot for your help! Much appreciate it!

[Star Strider]

My pleasure!