A standardized examâ€™s scores are normally distributed. In a recent? year, the mean test score was 1475 and the standard deviation was 311. The test scores of three students selected at random are? 1900, 1240, and 2170. Find the? z-scores that correspond to each valueand determine if that value would be considered unusual. Use the criteria at the bottom of page 241 to determine if the value would be considered unusual.a. Find the? z-score for 1900.b. Find the? z-score for 1240.c. Find the? z-score for 2170.