A data set is shown in the table. The line of best fit modeling the data is [tex]\(y = 2.69x - 7.95\)[/tex].

[tex]\[
\begin{tabular}{|c|c|}
\hline
x & y \\
\hline
1 & -5.1 \\
\hline
2 & -3.2 \\
\hline
3 & 1.0 \\
\hline
4 & 2.3 \\
\hline
5 & 5.6 \\
\hline
\end{tabular}
\][/tex]

What is the residual value when [tex]\(x = 3\)[/tex]?

A. -0.88
B. -0.12
C. 0.12
D. 0.88



Answer :

To calculate the residual value when [tex]\( x = 3 \)[/tex] given the line of best fit [tex]\( y = 2.69x - 7.95 \)[/tex]:

1. Identify the observed value from the data table:
- For [tex]\( x = 3 \)[/tex], the observed [tex]\( y \)[/tex] value is [tex]\( 1.0 \)[/tex].

2. Calculate the predicted [tex]\( y \)[/tex] value using the line of best fit:
- The line of best fit is given by the equation [tex]\( y = 2.69x - 7.95 \)[/tex].
- Substitute [tex]\( x = 3 \)[/tex] into this equation to get the predicted [tex]\( y \)[/tex] value:
[tex]\[ y_{\text{predicted}} = 2.69 \times 3 - 7.95 \][/tex]
- This simplifies to:
[tex]\[ y_{\text{predicted}} = 8.07 - 7.95 \][/tex]
[tex]\[ y_{\text{predicted}} = 0.12 \][/tex]

3. Calculate the residual:
- The residual is the difference between the observed [tex]\( y \)[/tex] value and the predicted [tex]\( y \)[/tex] value:
[tex]\[ \text{residual} = y_{\text{observed}} - y_{\text{predicted}} \][/tex]
- Using the observed [tex]\( y \)[/tex] value [tex]\( 1.0 \)[/tex] and the predicted [tex]\( y \)[/tex] value [tex]\( 0.12 \)[/tex]:
[tex]\[ \text{residual} = 1.0 - 0.12 \][/tex]
[tex]\[ \text{residual} = 0.88 \][/tex]

Therefore, the residual value when [tex]\( x = 3 \)[/tex] is [tex]\( \boxed{0.88} \)[/tex].