Chapter 5.3, Problem 41E

Consider the scatterplot of acrylamide concentration versus frying time from the previous exercise.

1. a. Which observation is potentially influential? Explain the reason for your choice.
2. b. When the potentially influential observation is deleted from the data set, the equation of the least-squares line using the remaining five observations $\hat{y}=-44+0.83x$. Use this equation to predict the acrylamide concentration for a frying time of 270 seconds. 1 low does this prediction compare to the prediction made in the previous exercise?

5.40 Acrylamide is a chemical that is sometimes found in cooked starchy foods and which is thought to increase the risk of certain kinds of cancer. The paper “A Statistical Regression Model for the Estimation of Acrylamide Concentrations in French Fries for Excess Lifetime Cancer Risk Assessment” (Food and Chemical Toxicology [2012]: 3867–3876) describes a study to investigate the effect of x = Frying time (in seconds) and y = Acrylamide concentration (in micrograms per kilogram) in French fries. The data in the accompanying table are approximate values read from a graph that appeared in the paper.

1. a. Construct a scatterplot of these data.
2. b. Find the equation of the least-squares line. Based on this line, what would you predict acrylamide concentration to be for a frying time of 270 seconds? What is the residual associated with the observation (270, 185)?