The Mother of a 16-Year-Old Boy with Juvenile Arthritis Was

The mother of a 16-year-old boy with juvenile arthritis was told by a friend of special magnetic bracelets and a magnetic mattress that had helped her husband's arthritis. Her friend gave her a couple of pamphlets that described the unique pain-relieving and "healing" properties of the special magnetic bracelets and mattress. The pamphlets referred to "scientific studies conducted at a major university." The literature also provided several personal testimonials from people who claimed to have benefited from wearing the magnetic bracelets and sleeping on the magnetic mattress. The mother spent more than $500 on the magnetic mattress and bracelets but her son's arthritis symptoms did not improve. What was the mother's mistake?

A) She confused statistical significance with practical significance.
B) She mistakenly accepted personal anecdotes and testimonials as scientific evidence.
C) She failed to realize that laboratory experiments usually do not generalize to real-world situations in everyday life.
D) She forgot that only a positive correlation can indicate a true cause-and-effect relationship.