Benzodiazepine tranquilizers (such as Valium) exert their physiological effects by binding to specific receptors in the brain. This binding then interacts with a neurotransmitter, γ-amino butyric acid...

Benzodiazepine tranquilizers (such as Valium) exert their physiological effects by binding to specific receptors in the brain. This binding then interacts with a neurotransmitter, γ-amino butyric acid (GABA), to cause changes in nerve activity. Because most direct methods of studying the effects of receptor binding are not appropriate for living human subjects, Hommer and coworkers* sought to study the effects of different doses of Valium on various readily measured physiological variables. They then looked at the correlations among these variables to attempt to identify those that were most strongly linked to the effect of the drug. Two of these variables were the sedation state S induced by the drug and the blood level of the hormone cortisol C (the data are in Table D-1, Appendix D). Is there a significant correlation between these two variables? (Use S as the dependent variable.)

Table D-1