For a 1000 x 1000 matrix of normal random numbers, I wish to verify that the mean is zero and the variance is 1. Which of the following can I use?

		check = [mean(x(:)) var(x(:))]
		check = [mean(mean(x)) var(x(:))]
		check = [mean(mean(x)) var(var(x))]
		check = [mean(x(:)) std(x(:)).^2]

multiple answers may be true please select all that are true