Consider the following data for two variables, $x$ and $y$
$$\begin{array}{c|cccccc}
\boldsymbol{x} & 22 & 24 & 26 & 30 & 35 & 40 \\
\hline \boldsymbol{y} & 12 & 21 & 33 & 35 & 40 & 36
\end{array}$$
a. Develop an estimated regression equation for the data of the form $\hat{y}=b_{0}+b_{1} x$
b. Use the results from part (a) to test for a significant relationship between $x$ and $y$ Use $\alpha=.05$
c. Develop a scatter diagram for the data. Does the scatter diagram suggest an estimated regression equation of the form $\hat{y}=b_{0}+b_{1} x+b_{2} x^{2} ?$ Explain.
d. Develop an estimated regression equation for the data of the form $\hat{y}=b_{0}+b_{1} x+$ $b_{2} x^{2}$
e. $\quad$ Refer to part (d). Is the relationship between $x, x^{2},$ and $y$ significant? Use $\alpha=.05$
f. Predict the value of $y$ when $x=25$