### 8.1 Assigning a Measure to Likelihood

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• Math Help

In Example 1, note the different ways that the probabilities can be written.

• The probability of a meteoroid hitting Earth, 0.75, can also be written as or 75%.
• The probability of Apophis hitting Earth, 0, can also be written as 0%.
• The probability of 2000 SG344 hitting Earth, , can also be written as 0.0023 or 0.23%.
• The probability of 2008 TC3 hitting Earth, 1, can also be written as 100%.
• Consumer Suggestion

When meteorologists provide a weather forecast, they are determining how likely a certain weather pattern is to occur within a given time. Typically, forecasts reach a range of 7 to 10 days into the future. For more information on weather forecasting, visit the National Weather Service.

• Checkpoint Solution
1. Equally likely to happen or not happen; it is generally considered that there is a 50-50 chance that a given person will be male or female. So, there is a 50% chance that a family's oldest child is a girl.
2. Unlikely; Assuming there is a 50% chance that a child is a girl, there is a (0.50)(0.50) = 0.25 or 25% chance that both children are girls.

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```  _____     _____     ______   _    _    ______
/  ___||  |  ___||  /_   _// | || | || |      \\
| // __    | ||__      | ||   | || | || |  --  //
| \\_\ ||  | ||__     _| ||   | \\_/ || |  --  \\
\____//   |_____||  /__//     \____//  |______//
`---`    `-----`   `--`       `---`   `------`

```