Insomnia and education. Is insomnia related to education status? Researchers at the Universities of Memphis, Alabama at Birmingham, and Tennessee investigated this question in the Journal of Abnormal Psychology (February 2005). Adults living in Tennessee were selected to participate in the study using a random-digit telephone dialing procedure. Two of the many variables measured for each of the 575 study participants were number of years of education and insomnia status (normal sleeper or chronic insomnia). The researchers discovered that the fewer the years of education, the more likely the person was to have chronic insomnia

(a) Identify the population and sample of interest to the researchers.

(b) Describe the variables measured in the study as quantitative or qualitative.

(c) What inference did the researchers make?