How do you calculate what the deciles of the standard normal distribution (that is, the 10, 20, 30, ... , 90 percentiles)?

To calculate the deciles of the standard normal distribution (the 10th, 20th, 30th, ..., 90th percentiles), you start by looking at the standard normal table. You need to find the Z-scores corresponding to the probabilities 0.50, 0.60, 0.70, 0.80, and 0.90. For example, the Z-score for 0.90 is approximately 1.28. Since the standard normal distribution is symmetric, the values for the upper percentiles (0.90, 0.80, etc.) correspond directly to negative Z-scores for the lower percentiles (0.10, 0.20, etc.). Specifically: * The Z-score for the 10th percentile (0.10) will be -1.28 (the negative of 0.90). * The Z-score for the 20th percentile (0.20) will be -0.84 (the negative of 0.80). * This symmetry continues for the other percentiles as well. Thus, you only need to find the Z-scores for the upper half and apply the negative sign for the corresponding lower percentiles.