A silver-plating process is being used to coat a certain type of serving tray. When the process is in control, the: thickness of the silver on the trays will vary randomly following a normal distribution with a mean of 0.02 millimeter and a standard deviation of 0.005 millimeter. Suppose that the next 12 trays examined show the following thicknesses of silver: 0.019, 0.021, 0.020, 0.019, 0.020, 0.018, 0.023, 0.021, 0.024, 0.022, 0.023, and 0.022. Use the runs test to determine if the fluctuations in thickness from one tray to another are random. Let a = 0.05.