An X bar chart includes the following data: The mean of data ranges from negative 30 to 30 on the Y axis. The group ranges from 2 to 20 on the x axis. The upper control limit is 26.17. The average is 2.31. The lower control limit is negative 21.55 The mean travels in a positive direction until approximately 11 on the X axis, when it drop sharply to negative 20. It rises to 20 immediately. The mean never crosses either the upper or lower control limits.