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1. Articles included:

• Contradictory results by Ann Landers and another survey
• pages 17-18 from the unit "Insights into Data' (from Mathematics in Context series)
• "Shaky statistics" (reproduced below)

The introduction of air bags has saved some lives and lost some. The National Highway Traffic Safety Administration (NHTSA) has made several attempts to estimate the number of lives air bags saved since their introduction. Using computer models, the NHTSA estimated that they have saved over 17,000 lives.

A study that compared the number of drivers and front-seat passengers, who died in 2,880 cars equipped with air bags, with the number who died in crashes of 5,237 cars without air bags, concluded that there were about 10% less fatalities in cars equipped with air bags. From this they estimated that there would have been 1,136 more fatalities if air bags had not been introduced. However, the data base used for this study did not have good information on the use of seat belts and so the two groups may have differed significantly as regards to the use of seat belts. This makes it hard to determine the contribution of air bags.

It has been felt that seat belts are the chief protector and safety experts have considered air bags as supplimentary. But air bags were designed to inflate with the force to save a 169-pound man who is not wearing a seat belt. When this rule was established few people wore seat belts but now 70% do.

The NHTSA estimates that 145 people have been saved on the passenger side by air bags, all of whom are adults, while air bags have killed 36 people, all but one of whom are children. The NHTSA is proposing that the force of the bags be reduced and "smart" bags be introduced that can adjust for small children.

The changes in air bag regulations will have the effect of changing the ratio of the number of people saved to killed. The fact that these involve different groups, adults and children, makes this a difficult regulatory decision. The lack of reliable estimates for the number saved by air bags and for the use of seat belts makes this decision even more difficult.

2. Worksheet (last page of the packet)

Adapted from "How likely is it?" (Connected Mathematics Project)

Name______________________
Date_______________________
Set_________________________

Use the below data to answer the following questions. If there is not enough information to answer a question, explain what additional information you would need.

In 1988 47,093 people were killed in car crashes and 3,486 people were killed in motorcycle crashes in the United States.

In the U.S. 40% of all deaths of people between the ages of 15 and 19 result from motor-vehicle crashes. Alcohol is involved in about half of these crashes.

Males outnumber females as fatal crash victims by an average of 2 to 1.

55% of motorcycle deaths occurred on weekends.

In 1988, the car with the lowest death rate was the Volvo 740/760 four-door, while the car with the highest death rate was the Chevrolet Corvette.

1. Which is safer to drive, a car or a motorcycle?
2. What percent of all deaths of 15-19 year olds result from alcohol related motor-vehicle crashes?
3. Is a particular motorcycle rider more likely to be in a fatal crash during the week or during the weekend?
4. Are males worse drivers than females?
5. Your family is trying to decide which used car to buy. Are you less likely to have an accident if you buy a Volvo 740 or 760 than if you buy a Chevrolet Corvette?

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