Understanding z scores

Understanding z scores

Standard scoresStandard scores assume a normal distributionThey provide a method of expressing any score in a distribution in terms of its distance from the mean in standard deviation units2

Z-scoreA raw score by itself is rather meaningless.What gives the score meaning is its deviation from the meanA Z score expresses this value in standard deviation units3

Z-score

4Raw score

Mean

Standard deviation

Z score formula

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Z score computation

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