The data set you provided is:

2, 3, 5, 5, 5, 15.

To identify the outlier, we can observe that most of the values are clustered around 2 to 5, while 15 is significantly higher than the others. This large deviation makes 15 appear to be the outlier.

Would you like to see a more formal method to detect this outlier, such as calculating the interquartile range (IQR) or using standard deviation?

Here are 5 questions related to outliers:

1. What are some formal methods for detecting outliers in a data set?
2. How does the interquartile range (IQR) help in identifying outliers?
3. Why is it important to detect outliers in a statistical analysis?
4. Can outliers affect the mean and median of a data set? How?
5. Are there any scenarios where an outlier should not be removed from a data set?

Tip: Always examine the context of the data before deciding to remove or address outliers. Sometimes outliers are legitimate and provide valuable insights.