Standard IQ scores have a mean of 100 and a standard deviation of 15. When Yolanda was in 1st grade, her IQ was measured to be 80. When she was in 3rd grade, it was measured to be 90. Her psychologist wants to express Yolanda's IQ in terms of a z-score. To do so, the psychologist takes the average of the two scores (the one from 1st grade and the one from 3rd grade) and then computes the z-score. What will the z-score of Yolanda's IQ be? Standard IQ scores have a mean of 100 and a standard deviation of 15. When Yolanda was in 1st grade, her IQ was measured to be 80. When she was in 3rd grade, it was measured to be 90. Her psychologist wants to express Yolanda's IQ in terms of a z-score. To do so, the psychologist takes the average of the two scores (the one from 1st grade and the one from 3rd grade) and then computes the z-score. What will the z-score of Yolanda's IQ be? -1 0 1 There's not enough information to solve this