The accompanying data on y= glucose concentration (g/L) and x= fermentation time (days...

The accompanying data on y= glucose concentration (g/L) and x= fermentation time (days) for a particular blend of malt liquor were read from a scatterplot in the article “Improving Fermentation Productivity with Reverse Osmosis” (Food Technology [1984]: 92– 96):

a. Construct a scatterplot for these data. Based on the scatterplot, what type of model would you suggest?

b. Minitab output resulting from fitting a multiple regression model with x₁ = x and x₂ = x² is shown here. Does this quadratic model specify a useful relationship between y and x?

c. Could the quadratic term have been eliminated? That is, would a simple linear model have sufficed? Test using a .05 significance level.