Chi-Square random numbers
R = distfun_chi2rnd(k) R = distfun_chi2rnd(k,[m,n]) R = distfun_chi2rnd(k,m,n)
a matrix of doubles, the number of degrees of freedom, k>0 (can be non integer)
a 1-by-1 matrix of floating point integers, the number of rows of R
a 1-by-1 matrix of floating point integers, the number of columns of R
a matrix of doubles, the positive random numbers.
Generates random variables from the Chi-Sqaure distribution function.
Any scalar input argument is expanded to a matrix of doubles of the same size as the other input arguments.
// set the initial seed for tests distfun_seedset(1); // Test with expanded k computed = distfun_chi2rnd((1:6)') expected = [ 1.8608435 1.2995079 2.8402769 0.9538728 4.5217814 2.9898461 ] // Check R = distfun_chi2rnd(k,v) computed = distfun_chi2rnd(2,[4 5]) // Check mean and variance N = 50000; k = 3; computed = distfun_chi2rnd(k,[1 N]); c = mean(computed(1:N)) d = st_deviation(computed(1:N) ) [M,V] = distfun_chi2stat (k) // Compare histogram of random numbers // with PDF. k=5; R=distfun_chi2rnd(k,10000,1); scf(); histplot(30,R); x=linspace(0,25,1000); y=distfun_chi2pdf(x,k); plot(x,y,"b-"); xtitle("Chi-square random numbers","X","Density"); legend(["Empirical","PDF"]); | ![]() | ![]() |
http://en.wikipedia.org/wiki/Chi-squared_distribution