Each number on the horizontal line corresponds to the z-score. The standard normal distribution is a type of special normal distribution with a mean (µ) of 0 and a standard deviation of 1.Ī standard normal distribution always has a mean of zero and has intervals that increase by 1. What is a Standard Normal Distribution?Ī Normal Standard Distribution curve is a symmetric distribution where the area under the normal curve is 1 or 100%. Similarly, if the Z value is negative, it means the value (x) is below the mean.
If the Z value is positive, it indicates that the value or score (x) is above the mean. Technically, a Z-score tells you how many standard deviations value (x) are below or above the population mean (µ). In other words, the Z-score measures the dispersion of data.
Z scores (Z value) is the number of standard deviations a score or a value (x) is away from the mean.
