Continuous recording of heart rate can be used to obtain information about the level of exercise intensity or physical strain during sports participation, work, or other daily activities. The article

“The Relationship Between Heart Rate and Oxygen Uptake During Non-Steady State Exercise” (Ergonomics, 2000:

1578–1592) reported on a study to investigate using heart rate response (x, as a percentage of the maximum rate) to predict oxygen uptake (y, as a percentage of maximum uptake) during exercise. The accompanying data was read from a graph in the article.

For each of these four data sets, the values of the summary statistics , and are virtually identical, so all quantities computed from these five will be essentially identical for the four sets—the least squares line , SSE, s2, r2, t intervals, t statistics, and so on. The summary statistics provide no way of distinguishing among the four data sets. Based on a scatter plot and a residual plot for each set, comment on the appropriateness or inappropriateness of fitting a straight-line model; include in your comments any specific suggestions for how a “straight-line analysis” might be modified or qualified.