04: Standard Deviation: Scores Distribution
Standard Deviation
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- Standard Deviations represent the spread of a distribution of scores and are the most commonly used standard score
- They are also the basis for most other standard scores.
- As discussed in Unit I:
- Under a bell-shaped curve, 68% of scores fall within one SD of the mean.
- About 95% fall within two SD’s
- About 99% fall within three SD’s