The observed values are given in the table shown in the question. The line of best fit is given to be:
![y=-1.1x+90.31](https://img.qammunity.org/2023/formulas/mathematics/college/lf1oxxs5og0gyuh4qq4508v5vergh3jw84.png)
where x is the average monthly temperature and y is the heating cost.
A residual is a difference between the observed y-value (from scatter plot) and the predicted y-value (from regression equation line). The formula will be:
![Residual=Observed\text{ }y\text{ }value-Predicted\text{ }y\text{ }value](https://img.qammunity.org/2023/formulas/mathematics/college/rpr5y5gdla5zqccnpbhu4kvq5lnyn3g136.png)
QUESTION A
The average monthly temperature is 24.9:
![x=24.9](https://img.qammunity.org/2023/formulas/mathematics/college/y8k3qww8yxxw0bi4ikim281b8gweu4nb9t.png)
Observed cost:
![y=51.00](https://img.qammunity.org/2023/formulas/mathematics/college/q8du315kfa40vjfd944vls3oesmxwimxzd.png)
Predicted cost:
![\begin{gathered} y=-1.1(24.9)+90.31=-27.39+90.31 \\ y=62.92 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/h32ualj87hojukmczu5n5e39pgstpo41cc.png)
Residual:
![\begin{gathered} R=51.00-62.92 \\ R=-11.92 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/u04gchkifyrrfgu7xv88nvp0ubjj0agjm7.png)
QUESTION B
The average monthly temperature is 35.9:
![x=35.9](https://img.qammunity.org/2023/formulas/mathematics/college/3bs4yd7iqrq521eu5fr11c6vj9yyjjjxr8.png)
Observed cost:
![y=67.00](https://img.qammunity.org/2023/formulas/mathematics/college/k6smltoowo5f1cm8r3lbecoqyeg8w0nuaw.png)
Predicted cost:
![\begin{gathered} y=-1.1(35.9)+90.31=-39.49+90.31 \\ y=50.82 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/8cxezvo3tkbkedyn99veabfpbe105qcq45.png)
Residual:
![\begin{gathered} R=67.00-50.82 \\ R=16.18 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/wmiz5y4lz14kcfdoem8htjf4bfl5y8x21s.png)