What does a z-score represent in statistics?

A z-score is a statistical measurement that describes a value's position relative to the mean of a group of values, specifically indicating how many standard deviations that value is away from the mean. When a z-score is calculated, it gives insight into the relative standing of a data point within a distribution, allowing for comparison between different data points or different distributions.

For example, if a z-score is 2, this indicates that the value is 2 standard deviations above the mean, while a z-score of -1 signifies that the value is 1 standard deviation below the mean. This standardization is crucial in statistics as it enables analysts to understand how unusual or typical a value is within a given dataset. This understanding is pivotal in various applications, such as hypothesis testing and identifying outliers.

Other options do not correctly define the z-score; measures of central tendency refer to averages like mean and median, confidence levels pertain to the probability that a parameter lies within a specified range, and data visualization involves charting or graphing data to depict relationships or distributions, none of which relate to the concept of a z-score.