MATLAB: Function ztest not found in R2015a

MATLABztest missing in matlab 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

Best Answer

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.

Related Solutions

MATLAB: Obtaining the p value from the t stat

If you have the Statistics Toolbox, the tcdf function will do what you want.

If not, the t-probability calculation 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’ are the degrees-of-freedom. (Note that ‘tdist1T’ calls ‘tdist2T’.)

MATLAB: How to calculate 2-tailed P value using t value and degree of freedom

You can simply cut to the chase and calculate it directly:

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

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

Best Answer

Related Solutions

MATLAB: Obtaining the p value from the t stat

MATLAB: How to calculate 2-tailed P value using t value and degree of freedom

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