Day 41 A ten-year nationwide study of the effectiveness of wearing a helmet while bicycling indicates that ten years ago, approximately 35 percent of all bicyclists reported wearing helmets
The following appeared in a health newsletter.
“A ten-year nationwide study of the effectiveness of wearing a helmet while bicycling indicates that ten years ago, approximately 35 percent of all bicyclists reported wearing helmets, whereas today that number is nearly 80 percent. Another study, however, suggests that during the same ten-year period, the number of bicycle-related accidents has increased 200 percent. These results demonstrate that bicyclists feel safer because they are wearing helmets, and they take more risks as a result. Thus, to reduce the number of serious injuries from bicycle accidents, the government should concentrate more on educating people about bicycle safety and less on encouraging or requiring bicyclists to wear helmets.”
Write a response in which you examine the stated and/or unstated assumptions of the argument. Be sure to explain how the argument depends on these assumptions and what the implications are for the argument if the assumptions prove unwarranted.
五问：
（1）“A ten-year nationwide study of the effectiveness of wearing a helmet while bicycling indicates that ten years ago, approximately 35 percent of all bicyclists reported wearing helmets, whereas today that number is nearly 80 percent. Another study, however, suggests that during the same ten-year period, the number of bicycle-related accidents has increased 200 percent”是事实， “Thus, to reduce the number of serious injuries from bicycle accidents, the government should concentrate more on educating people about bicycle safety and less on encouraging or requiring bicyclists to wear helmets”是结论，值得反驳吗？
（2）对于原文给出的第一项调查研究，我们能否简单地依据人们的报告来判定戴头盔的自行车手的比例？戴了头盔的自行车手一定愿意告诉别人自己戴了头盔吗？原文给出的第二项研究中提到的与自行车相关的事故一定是由自行车手导致的吗？或者说一定与自行车手本身相关吗？
（3）原文使用了两项调查研究进行对比，并且也强调了两项研究的时间段一致；但是同学们应当思考，两项研究仅仅时间段一致就能够用于对比了吗？你能想出可能影响两项调查研究进行对比的要素吗？例如：样本的选择可能并不一致。
（4）发生更多的车祸一定是因为戴了头盔的自行车手更大胆了吗？你能否想出其他可能导致自行车手的安全事故增多的原因？例如：开车的司机不遵守交通规则，没有专用的自行车道等。
（5）政府推行的两项措施之间一定是非此即彼的关系吗？如果两项措施都能被证明对自行车手的安全有利，这两项措施是否应当同时被推行？
