Skewed sample size less than 30
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The document discusses using parametric versus non-parametric tests based on sample size for skewed distributions. For skewed distributions with a sample size less than 30, a non-parametric test is recommended. For skewed distributions with a sample size greater than or equal to 30, a parametric test is recommended. It provides examples analyzing the correlation between ACT scores and sense of school belongingness using both approaches.
Skewed sample size less than 30
- 1. Are the samples sizes of the skewed distributions less than 30 or are they greater than or equal to 30? Skewed LESS than 30 Skewed GREATER or EQUAL to 30
- 2. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? Less than of 30
- 3. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? Less than of 30
- 4. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? −𝟐.𝟔𝟖𝟒 .𝟒𝟒𝟖 = -5.992 or negatively skewed Less than of 30
- 5. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? −𝟐.𝟔𝟖𝟒 .𝟒𝟒𝟖 = -5.992 or negatively skewed Because the sample size for this skewed distribution is less than 30 we will use a non-parametric test. Less than of 30
- 6. Next Example
- 7. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? Greater than or equal to 30
- 8. • What is the correlation between ACT scores (scaled) and sense of school belongingness (scaled 1-10)? Greater than or equal to 30 Because the sample size for this skewed distribution is GREATER or EQUAL to 30 we will use a parametric test.
- 9. Return to the original problem and ask: Are the samples sizes of the skewed distributions less than 30 or are they greater than or equal to 30? Skewed LESS than 30 Skewed GREATER or EQUAL to 30