H.W No. 2:
The accompanying data resulted from a study carried out to examine the relationship between a measure of the corrosion of reinforcement ( y ) and the concentration of the corrosion inhibitor solution in concrete pores ( x , in ppm ):
\[
\begin{array}{l}
\text { x: } 2.5,5.03,7.6,11.6,13,19.6,26.2,33,40,50,55 \\
\text { y: } 7.68,6.95,6.3,5.75,5.01,1.43,0.93,0.72,0.68,0.65,0.56
\end{array}
\]
a. Construct a scatter plot of the data. Dose the simple linear regression appear to be logical?
b. Calculate the equation of the estimated regression line, use it to predict the value of the corrosion rate that would be observed for a concentration of 33 ppm , and calculate corresponding residual.
c. Estimate the standard deviation of observation about the true regression line.
