PSYC 3000 Lecture Notes - Lecture 4: Standard Deviation, Normal Distribution, Descriptive Statistics
9 Sep 2015
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Z-score: states how far a given score is from the mean, in standard deviation units z= ( y ) s: above mean = +z, below mean = -z. The absolute value of the z indicates how many standard deviations from the mean the score is located. Z is a measure of the rank of a score in a distribution. Transform compute variable target variable: z-score numeric expression: (score mean) / standard deviation click ok: z-score is in column beside standard deviation. A z-score gives us an indication of how unusual a score value is because it tells us how far it is from the mean. The larger a z-score is (negative or positive), the more unusual it is. To assess more precisely how unusual a score is, we will use a model of the distribution to which the score belongs. Appropriate for distributions whose shapes are unimodal and roughly symmetric.
