Consider the College Women’s data presented in Example
3.7 and the line of best fit. When estimating the line of best fit from a scatter diagram, the choice for the two points (x1, y1) and (x2, y2) to be used is somewhat arbitrary. When different points are used, slightly different values for b0 and b1 will result, but they should be approximately the same.
a. What points on the scatter diagram (Figure
3.27, p. 154) were used to estimate the slope and y-intercept in the example on page 150? What were the resulting estimates?
b. Use points (61, 95) and (67, 130) and find the approximate slope and y-intercept values.
c. Compare the values found in part b with those described in part a. How similar are they?
d. Compare both sets of estimates with the actual values of slope and y-intercept found in Example 3.7 on pages 150–151. Draw both estimated lines of best fit on the scatter diagram shown in Figure 3.26. How useful do you think estimated values might be? Explain.