Stat 1040
Chapter 8 Solutions

  1. d. (a has the wrong means, b has the wrong SD's, and c has too much correlation).

    1. Negative: older cars are less fuel-efficient.
    2. Richer people tend to own newer cars and maintain them better.

  3. .3. (It should be positive, but not as high as .9!)

  4. It is -1. (Sketch a scatter diagram if you have trouble seeing this).