Download Z Scores

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Z Scores
o Z- Scores help to make sense of a distribution by specifying the precise location of
each score in the distribution.
o Z- Scores allow us to compare different distributions by making them equivalent.
o Specifically:
 Transforming Z- Scores from raw scores creates a z-distribution where the
mean () is 0 and the SD () is 1.
 In a Z- distribution, 50% of the scores always fall above the mean, and 50% of
the scores always fall below the mean.
 Formula:
 
o The exact location is described by the Z- Score.
 Sign (+ or -) tells whether score is located above or below the mean.
 Number tells distance between score and mean in standard deviation units.
o Z-Scores can be converted back to raw scores.
 X = (z)() + 
Calculating Z Scores with SPSS
1. Click on the Analyze drop - down menu.
2. Highlight Descriptive Statistics.
3. Click on Descriptives.
4. Move the variables that you wish to analyze over into the box.
5. Click the box that says “save standardized values as variables”.
6. Click OK.
7. Close the output window.
8. A separate column will appear with the z- scores in it for each specific score.