Question 6.69

34. In Exercise 6 (page 278), you made a scatterplot of the length of an icicle and the number of minutes that water has been flowing over the icicle.

  1. The equation of the least-squares regression line for predicting icicle length from time is

    Redo your scatterplot of icicle length against time from Exercise 6. Add a graph of the least-squares regression line to the plot. Be sure to show how you were able to plot the line starting with its equation.

  2. Use the “up-and-across” method illustrated in Figure 6.6 (page 251) to show the predicted length of the icicle after 75 minutes. Approximately what is the predicted length?
  3. Now use the equation of the least-squares regression line to predict the length of the icicle after 75 minutes.