function v = s_variance(Z)

%VARIANCE computes the sample variance of the data
%
%INPUTS: Z = Data values Z(i) , i=1:n
%
%OUTPUTS: v = variance of Z

n = length(Z) ;

%compute variance

mu = (1/n)* (ones(1,n)* Z) ;

v = (1/(n-1))*(Z - mu * ones(n,1))'*(Z - mu * ones(n,1)) ;