The correct answer to this question is:

• "-1 and 1"

The correlation coefficient, denoted by $r$, measures the strength and direction of the linear relationship between two variables and always falls within the range $-1 \leq r \leq 1$.

• If $r = 1$, it indicates a perfect positive linear correlation.
• If $r = -1$, it indicates a perfect negative linear correlation.
• If $r = 0$, it suggests no linear correlation.

Would you like further details on how the correlation coefficient is interpreted?

Here are some related questions to expand your understanding:

1. What does it mean if the correlation coefficient $r$ is close to 0?
2. How is the correlation coefficient calculated between two variables?
3. What are some limitations of using the correlation coefficient?
4. Can a correlation coefficient alone determine causation between two variables?
5. How does the correlation coefficient relate to covariance?

Tip: Remember that correlation only indicates the strength and direction of a linear relationship; it does not imply causation.