The following data are a result of an investigation as to the effect of reaction temperature $x$ on percent conversion of a chemical process $y$. (See Myers, Montgomery and Anderson-Cook, 2009.) Fit a simple linear regression, and use a lack-of-fit test to determine if the model is adequate. Discuss.
$$
\begin{array}{ccc}
& \text { Temperature } & \text { Conversion } \\
\text { Observation } & \left({ }^{\circ} \mathrm{C}\right), x & (\%), y \\
\hline 1 & 200 & 43 \\
2 & 250 & 78 \\
3 & 200 & 69 \\
4 & 250 & 73 \\
5 & 189.65 & 48 \\
6 & 260.35 & 78 \\
7 & 225 & 65 \\
8 & 225 & 74 \\
9 & 225 & 76 \\
10 & 225 & 79 \\
11 & 225 & 83 \\
12 & 225 & 81
\end{array}
$$