A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1532 and the standard deviation was 318. The test scores of four students selected at random are 1940, 1280, 2240, and 1430. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1940 is ]. (Round to two decimal places as needed.)