The z-score of a certain data point in the given statistical data is calculated through the equation, z-score = (x - m) / sd where x is the data point, m is the mean and sd is the standard deviation. Substituting the known values, z-score = (51.8 - 52.3) / 1.8 z-score = -0.277 Rounding the answer to the nearest tenth will give an answer of -0.3.