How to Generate White Gaussian Noise using Random Number Generator Block in Simulink?

I have to generate White Gaussian Noise with "Zero Mean" using Random Number Block in Simulink. The Random Number Block requires 4 inputs which are "Mean","Variance","Initial SEED" and "Sample Time".

Now for Mean the value will be "0", what about variance? will I have to put "Standard Deviation" or "Square of Standard Deviation" as "variance" input?