What is the purpose of a z score in educational assessments?

The purpose of a z score in educational assessments is to indicate how many standard deviations a score is from the mean. This statistical measure allows educators and researchers to understand the relative position of a specific score within a distribution of scores. By converting raw scores into z scores, one can easily compare scores from different assessments or those that may have different means and standard deviations. A z score of zero indicates that the score is exactly at the mean, while positive or negative values indicate how far and in what direction the score deviates from the mean. This can help in evaluating student performance, identifying outliers, and contributing to more informed decision-making in educational settings.

The other options do not relate to the function of a z score. Measuring attendance and calculating graduation rates involve different metrics and do not provide insights into score distributions. Determining class rank deals with ordering students based on their performance without the statistical context that a z score provides.