6.26 Remember what you ate. How well do people remem ber their past diet? Data are available for 91 people who were asked about their diet when they were 18 years old. Researchers asked them at about age 55 to describe their eating habits at age 18. For each subject, the researchers calculated the correlation between actual intakes of many foods at age 18 arid the intakes the subjects now remember. The median of the 91 correlations was r =0.217. The authors say, "We conclude that memory of food intake in the distant past is fair to poor."'^ Explain why r = 0.217 points to this conclusion.