I have no idea how the function works, here's just a few basic tips:
X1 = TruncatedGaussian(sigma1, range1, n) %first test
X2 = TruncatedGaussian(sigma2, range2, n2) %second test
X3 = TruncatedGaussian(sigma3, range3, n3) %third test
clf
hold on
plot(X1)
plot(X2)
plot(X3)
legend('test 1','test 2', 'test 3')