Miguel wrote the predicted and residual values for a data set using the line of best fit [tex]y=1.82x-4.3[/tex]. He left out two of the values.

[tex]\[
\begin{array}{|c|c|c|c|}
\hline
x & \text{Given} & \text{Predicted} & \text{Residual} \\
\hline
1 & -2.3 & -2.48 & 0.18 \\
\hline
2 & -0.9 & -0.66 & -0.24 \\
\hline
3 & 1.1 & a & -0.06 \\
\hline
4 & 3.1 & 2.98 & b \\
\hline
\end{array}
\][/tex]

Which represents the missing values of [tex]a[/tex] and [tex]b[/tex]?

A. [tex]a = 1.16[/tex] and [tex]b = 0.12[/tex]

B. [tex]a = 1.16[/tex] and [tex]b = -0.12[/tex]

C. [tex]a = 0.5[/tex] and [tex]b = 6.08[/tex]

D. [tex]a = 0.5[/tex] and [tex]b = -6.08[/tex]



Answer :

To determine the missing values [tex]\(a\)[/tex] and [tex]\(b\)[/tex] in the table, let's analyze the line of best fit [tex]\(y = 1.82x - 4.3\)[/tex].

1. Predicted Value for [tex]\(x = 3\)[/tex]:
Using the line of best fit formula:
[tex]\[ y_{predicted}(3) = 1.82 \times 3 - 4.3 \][/tex]
[tex]\[ y_{predicted}(3) = 5.46 - 4.3 \][/tex]
[tex]\[ y_{predicted}(3) = 1.16 \][/tex]
So, [tex]\(a\)[/tex] is the predicted value for [tex]\(x=3\)[/tex], and we found:
[tex]\[ a = 1.16 \][/tex]

2. Residual for [tex]\(x = 3\)[/tex]:
Given that the residual for [tex]\(x=3\)[/tex] is [tex]\(-0.06\)[/tex]. We can verify this:
[tex]\[ \text{Residual} = \text{Given} - \text{Predicted} \][/tex]
[tex]\[ -0.06 = 1.1 - 1.16 \][/tex]
This confirms the calculated predicted value [tex]\(a = 1.16\)[/tex].

3. Predicted Value for [tex]\(x = 4\)[/tex]:
Again, using the line of best fit formula:
[tex]\[ y_{predicted}(4) = 1.82 \times 4 - 4.3 \][/tex]
[tex]\[ y_{predicted}(4) = 7.28 - 4.3 \][/tex]
[tex]\[ y_{predicted}(4) = 2.98 \][/tex]
The predicted value for [tex]\(x=4\)[/tex] is [tex]\(\approx 2.98\)[/tex].

4. Residual for [tex]\(x = 4\)[/tex]:
The given value for [tex]\(x=4\)[/tex] is [tex]\(3.1\)[/tex]. The residual is calculated as:
[tex]\[ \text{Residual} = \text{Given} - \text{Predicted} \][/tex]
[tex]\[ b = 3.1 - 2.98 \][/tex]
[tex]\[ b \approx 0.12 \][/tex]

So, the missing values [tex]\(a\)[/tex] and [tex]\(b\)[/tex] are:
[tex]\[ a = 1.16 \quad \text{and} \quad b = 0.12 \][/tex]

Thus, the correct choice is:
- [tex]\(a = 1.16\)[/tex] and [tex]\(b = 0.12\)[/tex]