People who give, live longer, studies have shown. Now, a new study by University of Michigan researchers shows that why people volunteer—not whether they volunteer—is what really counts.

For the study, Konrath and colleagues analyzed data collected in 2008 and 2012 aiming at the same random samples of 3, 376 people. Overall, they found that just 2.3 percent of those who once worked as volunteers had died, compared to 4.3 percent of non-volunteers. They further found that how much people volunteered mattered as well—only 1.8 percent of regular volunteers died, compared with 2.5 percent of occasional volunteers.

Q: How did the researchers do the research?

By doing experiments.

Through field research.

By analyzing statistics.

Through group discussion.

细节理解题。根据第二中 “For the study, Konrath and colleagues analyzed data collected in 2008 and 2012 aiming at the same random samples of 3, 376 people. (在这项研究中，Konrath和他的同事分析了2008年和2012年收集的数据，目标是3376人的随机样本。)” 可知，研究者是通过分析数据来进行这项研究的。故选C。