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# Definition of Probability

## Probability = # of Favorable Outcomes/# of Possible Outcomes

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Odds of Death

Credit: Ma?a Cybelle Carpenter
Source: http://www.flickr.com/photos/maiacybelle/11507904624/
License: CC BY-NC 3.0

What's more likely to kill a child: a gun or a swimming pool? Is it more dangerous to drive or to fly? Should you worry about more about brain-eating amoebas or the chicken you're cooking for dinner? Probability can help you make sense of our dangerous world.

#### The Terrifying and the Likely

Most people have a healthy fear of death. However, they often fear the wrong things. Probability can help you determine whether you're likely to die from a certain cause. For instance, consider the dangers of guns and pools. According to economist Steven Levitt, there's a 1 in 11,000 chance that a private pool will kill a child. There's a 1 in 1,000,000 chance that a gun will kill a child. That means that pools are almost 1,000 times as dangerous as firearms to children. So why do people fear guns more than pools? Because guns appear scarier and television shows don't portray the true risks swimming pools pose to young children.

Credit: Michael Himbeault
Source: http://www.flickr.com/photos/riebart/5913500563/
License: CC BY-NC 3.0

Should you be more frightened of raw chicken or brain-eating amoebas? Brain-eating amoebas make the news, but food-borne illnesses cause many more deaths and hospitalizations each year. You're more likely to die from a poorly washed knife and cutting board than from amoebas. So why do people panic about the amoeba? Because they haven't done the math!

See for yourself: http://www.youtube.com/watch?v=Ps0waR0LBpo

#### Explore More

Watch the following video on the effectiveness of child car seats and then answer the questions below.

Why do people assume that car seats are safer than seatbelts for older children? How does the data tell a different story?

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