The news story discussed in Case Study 6.5 (pp. 132- 133) was head-lined “NIH study finds that coffee drinkers have lower risk of death” (www.nih.gov). The news story was based on an article published in The New England Journal of Medicine (Freedman et. al., 2012) that followed hundreds of thousands of older adults from 1995 to 2008 and examined the association between drinking coffee and longevity.
a. What are the null and alternative hypotheses for this study?
b. The authors concluded that those who drank coffee had a statistically significantly lower risk of death (during the time period of the study) than those who did not. Which type of error, type 1 or type 2, could have been made in making this conclusion?
c. Explain what a type 1 error and a type 2 error would be in this situation. Which one do you think is more serious? Explain.