10.2 Sampling sleep The 2011 Bedroom Sleep poll of a random sample of 1500 adults reported that respondents slept an average of 6.5 hours on weekdays and 7.2 hours on weekends, and that 21% of respondents got eight or more hours of sleep on weekdays, whereas 44% got eight or more hours of sleep on weekends (www.sleepfoundation.org).

a. To compare the means or the percentages using inferential methods, should you treat the samples on weekdays and weekends as independent samples or as dependent samples? Explain.

b. To compare these results to polls of other people taken in previous years, should you treat the samples in the two years as independent samples or as dependent samples?

Explain.