According to figures released by the New York City government, smoking among New York City teenagers is on a decline, continuing a trend that began more than a decade ago ( The New York Times , January 2, 2008). According to the New York City Youth Risk Behavior Survey, the teenage smoking rate dropped to 8.5% in 2007 from about 17.6% in 2001 and 23% in 1997. City officials attribute the lower smoking rate to factors including a cigarette tax increase, a ban on workplace smoking, and television and subway ads that graphically depict tobacco-related illnesses.

In a report, use the above information to

1. Calculate the probability that at least one in a group of 10 New York City teenagers smoked in 2007.

2. Calculate the probability that at least one in a group of 10 New York City teenagers smoked in 2001.

3. Calculate the probability that at least one in a group of 10 New York City teenagers smoked in 1997.

4. Comment on the smoking trend between 1997 and 2007.