For Exercises 2.44 and 2.45, see page 82; for 2.46, see page 84; for 2.47, see page 86; for 2.48 and 2.49, see page 88; for 2.50, see page 90; for 2.51, see page 90; for 2.52, see page 91; and for 2.53, see page 94.

Question 2.76

2.76 Always plot your data!

Four sets of data prepared by the statistician Frank Anscombe illustrate the dangers of calculating without first plotting the data.11

ansdata

  1. Without making scatterplots, find the correlation and the least-squares regression line for all four data sets. What do you notice? Use the regression line to predict for .
  2. Make a scatterplot for each of the data sets, and add the regression line to each plot.
  3. In which of the four cases would you be willing to use the regression line to describe the dependence of on ? Explain your answer in each case.