Final answer:
A z-score is the number of standard deviations that an attribute falls from the mean. A positive z-score indicates a value above the mean, while a negative z-score indicates a value below the mean.
Step-by-step explanation:
A z-score is the number of standard deviations that an attribute falls from the mean. They can be above or below the mean. A positive z-score indicates a value above the mean, while a negative z-score indicates a value below the mean. For example, if a student's z score is 2.0, it means that they scored two standard deviations above the class mean.