Ans. is 'd' i.e., 1.0 Thus the Z score for the woman in question is 1.0. Very simple funda to calculate Z score Normal variate indicates that the given observation is how many standard detion away from the mean. Here mean is 13.5 g/c11, SD is 1.5 g/dl and observation is 15 g/dl. That means observation (15 g/dl) is 1 SD (1.5 g/dl) away from mean (13.5 g/dl). So relative dete (Z-score) is 1. In same question, if we assume that the observed value is 16.5 (mean +- 2 SD) that means relative dete is 2 as the observed value is 2 SD away from mean.