Reference no: EM132907645

A study has been conducted to assess the relationship between consuming kiwifruit and sleep quality. Participants consisted of people with self-reported poor sleep quality who were interestd in participating in a sleep study. Participants were recruited from a college with about 70% of participants were undergraduates, with the remaining participants being graduate students and staff. The study took place over the course of 8 weeks. The quality of sleep was measured on both subjective and objective scales. Subjectively it was measured via a standardized questionnaire, the Pittsburgh Sleep Quality Index (PSQI), that contains questions about sleep habits over the past month; high scores represent poorer sleep quality. Objective sleep quality was measured using a sleep logger wristwatch, which measured sleep time and sleep efficiency. The first 4 weeks were used to collect baseline measurements of sleep quality. During the second 4 weeks of the study, participants were instructed to eat two kiwifruits each night in the hour before going to bed. At the end of the study, researchers compared the baseline sleep quality measurements to those taken after the 4 weeks of kiwifruit consumption. They found that after the month of kiwifruit consumption, sleep quality improved: averages from both the subjective and qualitative testing improved. In the closing statement of the paper reporting these results, the authors wrote: "consumption of 2 kiwifruit nightly 1 hour before bedtime for 4 weeks resulted in improved sleep duration and efficiency in individuals with self-reported sleep disturbances". Explain why the closing statement is potentially misleading, and name two features of the study design that inhibit the ability to prove a clear correlation between sleep and kiwi.