Happiness and Your Heart Researchers wanted to determine if there was an association between the level of happiness of an individual and their risk of heart disease. The researchers studied 1739 people over the course of 10 years. During this 10-year period, they interviewed the individuals and asked questions about their daily lives and the hassles they face. In addition, hypothetical scenarios were presented to determine how each individual would handle the situation. These interviews were videotaped and studied to assess the emotions of the individuals.
The researchers also determined which individuals in the study experienced any type of heart disease over the 10-year period. After their analysis, the researchers concluded that the happy individuals were less likely to experience heart disease.
(a) What type of observational study is this? Explain.
(b) What is the response variable? What is the explanatory variable?
(c) In the report, the researchers stated that “the research team also hasn’t ruled out that a common factor like genetics could be causing both the emotions and the heart disease.” Use the language introduced in this section to explain what this sentence means.