The document discusses whether variables are dichotomous or scaled when calculating correlations. It provides examples of correlations between ACT scores and whether students attended private or public school. One example has ACT scores as a scaled variable and school type as dichotomous. Another has lower and higher ACT scores as dichotomous and school type as dichotomous. It emphasizes determining if variables are both dichotomous, or if one is dichotomous and one is scaled.

1. Are both of the variables dichotomous or is one
variable dichotomous while the other is scaled?
Both Dichotomous
One Dichotomous /
One scaled

2. Example
• What is the correlation between ACT scores and private or
public school students?

3. Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between ACT scores and private or
public school students?

4. Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between ACT scores and private or
public school students?

5. Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between ACT scores and private or
public school students?
• What is the correlation between ACT scores (scaled) and
private or public school students (dichotomous)?

6. Next Example

7. • What is the correlation between lower and higher ACT scores
and private or public school students?
Next Example

8. Next Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between lower and higher ACT scores
and private or public school students?

9. Next Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between lower and higher ACT scores
and private or public school students?

10. Next Example
Both Dichotomous One Dichotomous / One scaled
• What is the correlation between lower and higher ACT scores
and private or public school students?
• What is the correlation between lower and higher
(dichotomous) ACT scores and private or public school
students (dichotomous) ?

11. Return to the original question:
Are both of the variables dichotomous or is one variable
dichotomous while the other is scaled?
Both Dichotomous One Dichotomous / One scaled