So for example, one standard deviation above the mean is going to be 18. One standard deviation below the mean is going to be equal to negative two. And so now using this distribution, we can actually answer this question. What is the probability that the woman is taller than the man? Well we can rewrite that question as saying, what is the probability that the random variable D is, what conditions would it be? Pause the video and think about it. Well the situations where the woman is taller than the man, if the woman is taller than the man, then this is going to be a negative value.