79) A diagnostic chart used to identify sources of variation, where the number and types of defects are tallied, is referred to as a(n) A) fishbone diagram B) X-bar chart C) Pareto chart D) process control chart 80) Consider a situation where the lower control limit of a percent defective chart is negative. It must be that A) the absolute value of the negative LCL must be taken to arrive at a positive value B) an error was made in computing the LCL because negative values are impossible C) the process is out of control and must be redesigned D) the lower limit is set to zero 81) Which of the following statements about causes of variation are true? I. Assignable variation is random in nature and cannot be eliminated or reduced. II. Chance variation cannot be completely eliminated unless there are significant methods, techniques, or equipment used in the process. III. Chance variation usually cannot be corrected, while assignable variation is correctable. A) I only B) II only C) II and III D) I and III 82) Which of the following statements about in-control and out-of-control processes are true? I. The mean chart and range chart always show that processes are in control. II. A mean chart can be in control, while a range chart can be out of control. III. A mean chart can be out of control, while a range chart can be in control. A) I only B) II only C) II and III D) I and