1.8:

Introduction to z Scores

JoVE 핵심
Analytical Chemistry
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JoVE 핵심 Analytical Chemistry
Introduction to z Scores

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01:05 min

April 04, 2024

A z score (or standardized value) is measured in units of the standard deviation. It indicates how many standard deviations the value x is above (to the right of) or below (to the left of) the mean, μ. Values of x that are larger than the mean have positive z scores, and values of x that are smaller than the mean have negative z scores. If x equals the mean, then x has a zero z score. It is important to note that the mean of the z scores is zero, and the standard deviation is one.

z scores help find outliers or unusual values in any data distribution. According to the range rule of thumb, outliers or unusual values have z scores less than -2 or greater than +2.