A standardized exam's scores are normaly distributed. In a recent year, the mean test score was 20.7 and the standard deviation was 5.3 . The test scores of four students selected at randorn are 15,23,9, and 36 . 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 2 -score for 36 is (Round to two decimal places as needed) Which values, if any, are unusual? Select the correct choice below and, If necessary, fe in the answer box within your choice. A. The unusual value(s) isare (Use a comma to separme answers as needed) B. None of the values are unusual..