Correlation Relationships 089099
1. **Problem Statement:** We are asked to identify which data sets correspond to specific values or characteristics of the sample correlation coefficient $r$ based on the descriptions of four graphs and their data.
2. **Recall the definition of $r$:** The sample correlation coefficient $r$ measures the strength and direction of a linear relationship between two variables. It ranges from $-1$ to $1$.
- $r = -1$ means a perfect negative linear relationship.
- $r$ close to $0$ means no linear relationship.
- Negative $r$ values indicate a negative (downward) trend.
3. **Analyze each graph and data set:**
- **Figure 1 (Top-left):** Points decrease perfectly along a straight line from top-left to bottom-right, so $r = -1$.
- **Figure 2 (Top-right):** Points show a strong but not perfect negative linear trend.
- **Figure 3 (Bottom-left):** Points scattered randomly, no trend, so $r$ close to $0$.
- **Figure 4 (Bottom-right):** Points show a negative but imperfect linear relationship.
4. **Match the data sets to the graphs:**
- Data set with $u,v$ decreases perfectly from (1,10) to (10,1) matching Figure 1, so $r = -1$.
- Data set with $x,y$ shows increasing trend, so not negative.
- Data set with $w,t$ is scattered, no clear trend, so $r$ close to $0$.
- Data set with $m,n$ shows a general downward trend but not perfect, so negative but imperfect.
5. **Answer each question:**
(a) $r = -1$ corresponds to the data set $(u,v)$ (Figure 1).
(b) Strongest negative linear relationship is also $(u,v)$ (Figure 1) since $r = -1$ is the strongest possible negative correlation.
(c) $r$ closest to $0$ corresponds to $(w,t)$ (Figure 3) with scattered points.
(d) Negative but not perfect linear relationship corresponds to $(m,n)$ (Figure 4).
**Final answers:**
(a) $(u,v)$
(b) $(u,v)$
(c) $(w,t)$
(d) $(m,n)$