Based on the normal curve in Figure 9.3 (pg. 94), which has a mean of 12 and a standard deviation of 3, what are the z-scores and percentiles for the following outcomes?

15 positive behaviors: z scores = 18 positive behaviors: z score = 21 positive behaviors: z score = 9 positive behaviors: z score = 6 positive behaviors; z score = 3 positive behaviors: z score = 12 positive behaviors: z scores =