Which of the Following Statements Is TRUE About Common Cause

Multiple Choice

Which of the following statements is TRUE about common cause variations?

A) They can be controlled and described in a non-statistical method.
B) They appear at random, and individual sources cannot be identified or explained.
C) They account for about 10 to 15 percent of the observed variation in a process.
D) They arise from external sources that are not inherent in the process.