A Z score, or standard score, is the number of standard deviations an observation is away from the mean of the corresponding reference population. It is a measurement of the value of a single observation in relationship to the scores of a group of observations (population). Z scores transform units of analysis into a standardized form, allowing for comparison of variables measured in different units. When population parameters are known, Z scores are powerful for locating an individual observation in relation to all observations. When population parameters are not known, the Z distribution (normal distribution) changes slightly. As such, Z scores are a fundamental concept in statistical analysis. The transformation of units of analysis into standardized units (units of standard deviation) can be seen in ...
Looks like you do not have access to this content.