How to use this table: Because the normal curve is symmetrical about a mean of zero (the left side being a mirror image of the right side), the areas corresponding to negative z-scores are identical to the areas of positive z-scores. For example, the areas corresponding to a z-score of 1.00 are the same as those areas of a z-score of +1.00. Z-scores are given in column A. Areas between (inside) the mean and the z-score are given in column B, and column C contains the area that lies beyond (outside) the z-score. And, since the curve is symmetric, each half of the curve contains .5000 of the total area.