The equation X = u + zo is used to convert z-scores to original values for a population. 'X' is the original value, 'u' is the population mean, 'z' is the z-score, and 'o' is the standard deviation. The z-score measures the deviation from the mean in standard deviations. To convert it back to the original scale, use the above equation. This helps to understand the original value of a standardized data point