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A standardized exam's scores are normally distributed. In a recent year, the mean test score was 21.1 and the standard deviation was 5.5. The test scores of four students selected at random are 15, 23, 9, and 37. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 15 is. (Round to two decimal places as needed.) The z-score for 23 is Round to two decimal places as needed.) The z-score for 9 is (Round to two decimal places as needed.) The z-score for 37 is (Round to two decimal places as needed.) Which values, if any, are unusual? Select the correct choice below and, if necessary, fill in the answer box within your choice. O A. The unusual value(s) is/are (Use a comma to separate answers as needed.) O B. None of the values are unusual. Next MacBOOK AL esc 20