# What is an Outlier?

An outlier is a number in a group of numbers that is much bigger or smaller than all the other numbers. It’s like the one piece of popcorn in a bag of jellybeans – it stands out because it’s so different from the rest.

#### How Do You Find an Outlier?

To find an outlier, you look at a set of numbers and see if any of them are very different from the others. Here’s an example:

• Imagine you have these test scores: 85, 87, 88, 90, 92, and 50.
• Most of the scores are in the 80s and 90s, but 50 is much lower than the rest. So, 50 is an outlier.

#### Why are Outliers Important?

1. Understanding Data: Outliers can tell us something unusual is happening. Maybe a student had a bad day, or maybe there was a mistake in recording the score.
2. Improving Accuracy: By spotting outliers, we can decide if they should be included or excluded from our data to get a more accurate picture.
3. Finding Mistakes: Sometimes, outliers help us find errors. For example, if most people run a race in 10 minutes, but one time is recorded as 1 minute, it’s likely a mistake.

#### Examples of Outliers in Real Life

• Weather: If most days are warm and one day is freezing cold, that cold day is an outlier.
• Sports: If a basketball player usually scores 10 points per game but scores 50 points in one game, that high score is an outlier.
• Shopping: If a toy usually costs \$20, but one store sells it for \$200, that price is an outlier.

#### How to Handle Outliers

1. Check for Errors: Make sure the outlier isn’t a mistake in the data.
2. Understand the Reason: Try to find out why the outlier is so different.
3. Decide What to Do: Sometimes you might keep the outlier, especially if it’s real and important. Other times, you might leave it out to get a clearer picture of the rest of the data.

#### Conclusion

An outlier is a number that’s very different from the others in a group. It helps us spot unusual patterns and errors. By understanding and handling outliers, we can make better decisions based on our data.