Which on the diagrams in the following Exhibit represent a control chart?
Diagram A is in the shape of an XY chart. The horizontal axis is labeled as Time. A lower control limit (LCL), control limit (CL), and upper control limit (UCL) have been m marked on the vertical axis of the chart. Lines zigzag up and down through the three control lines with sharp peaks and valleys. One point is above the UCL line. Three points lie below the LCL line.
Diagram B contains a single middle line with an oval at the right end. There are also three lines that angle upwards from the central line, and three lines that angle downward. Each of these six lines contains an oval at
their end farthest from the horizontal line. Each of the six angled lines has a branch that is parallel to the middle line. The end of these branch lines also contains an oval.
Diagram C starts at the left with a rectangle. From this rectangle, three more rectangles branch off at the same level. Further branching occurs off two of the three rectangles.
Diagram D starts at the left with a rectangle. From this rectangle, two lines, each with an arrow at the end, point to other rectangles.
A line with an arrow extends from each of these other rectangles to another rectangle, and so on, until a final rectangle is drawn at the right side.