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Understanding z scores. Standard scores. Standard scores assume a normal distribution They provide a method of expressing any score in a distribution in terms of its distance from the mean in standard deviation units. Z-score. A raw score by itself is rather meaningless.
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Standard scores • Standard scores assume a normal distribution • They provide a method of expressing any score in a distribution in terms of its distance from the mean in standard deviation units
Z-score • A raw score by itself is rather meaningless. • What gives the score meaning is its deviation from the mean • A Z score expresses this value in standard deviation units
Z-score Raw score Mean Standard deviation