Stat 10, UCLA
Chapter 8 Solutions

  1. d. (a has the wrong means, b has the wrong SD's, and c has too much correlation). With (a), the averages are too low. With (b), the SDs are too small. With (c), the SDs are too big and the correlation is too high.

    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. 0.62 -1.00
    -0.85 0.97
    0.06 -0.38

    1. -0.80
    2. 0.30
    3. 1.00

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

http://www.stat.ucla.edu/~dinov