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 frying time (in seconds) and 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.

Frying Time ......................... Acrylamide Concentration
150 ................................................... 155
240 ................................................... 120
240 ................................................... 190
270 ................................................... 185
300 ................................................... 140
300 ................................................... 270

a. If the goal is to learn how acrylamide concentration is related to frying time, which of these two variables is the dependent variable and which is the independent variable?

b. Construct a scatterplot of these data. Describe any interesting features of the scatterplot.