It is well-documented that watching TV, working on a computer, or any other activity involving artificial light can be harmful to sleep patterns. Researchers wanted to determine if the artificial light from e-Readers also disrupted sleep. In the study, 12 young adults were given either an iPad or printed book for four hours before bedtime. Then, they switched reading devices. Whether the individual received the iPad or book first was determined randomly. Bedtime was 10 p.m. and the time to fall asleep was measured each evening. It was found that participants took an average of 10 minutes longer to fall asleep after reading on an iPad. The P-value for the test was 0.009. Source: Anne-Marie Chang, et. al. "Evening Use of Light-Emitting eReaders Negatively Affects Sleep, Circarian Timing, and Next-Morning Alertness" PNAS 2015 112(4) 1232-1277. doi:10.1073/pnas.1418490112
(a) What is the research objective?
(b) What is the response variable? It is quantitative or qualitative?
(c) What is the treatment?
(d) Is this a designed experiment or observational study? What type?
(e) The null hypothesis for this test would be that there is no difference in time to fall asleep with
an e-Reader and printed book. The alternative is that there is a difference. Interpret the P-value.