1. Researchers examined the effects of gender and age on pain perception. McEntarfer, DiPirro, and Page (2005) examined the perception of pain, induced in the cold pressor test and its relationship to age and gender. Volunteers (40 men and 40 women), aged 18-23 and 65-81 years, immersed their dominant hand in a bucket of water kept at 2 C. Pain threshold was determined as the time taken to notice pain from the stimulus. Pain tolerance was determined as the time before the participant removed his or her hand from the water, presumably because the pain became too intense. Analyses revealed that pain thresholds remain constant across age and gender, but that women had lower pain tolerance than men. Also, pain tolerance was lower for older adults than for younger adults. (15 pts)
   1. Is this an experiment, correlational study, or quasi-experiment? Explain your answer.
   2. Does the above study have an independent, subject, or dependent variable? If yes, identify each.
   3. Can the researches make any cause and effect conclusions based on this study? Why or why not?