4. (10 points) You plan to plot 3 points on a control chart with the following two rules: Rule 1 if the second point is larger than the first point, then the process is out of control. Rule 2: if all three points fall above the center line, then the process is out of control. Assume that the quality characteristic is symmetric around its mean and the results of these two rules are independent. Estimate the overall type I error.