Exercises

1. Plot the following statistics as a function of the standard deviation of X's error. Use values of 0, 5, 10, 15, and 20 for the standard deviation of X error. Leave the standard deviation of the error of Y at 0.0.
  1. reliability of X
  2. Pearson's r
  3. slope
  4. standard error of the estimate.
2. Repeat Exercise 1 except vary the standard deviation of the error of Y and set the standard deviation of the error of X to 0.0. What statistic is unaffected by the error in Y? (Ignore slight differences due to sampling variance in the simulation.)
3. Why does increasing the error in Y affect the standard error of the estimate?