Outlier
Topic of Descriptive statistics, part of Data analysis
Outlier
| Type | Topic |
| Taught in | Descriptive statistics |
| Part | Data analysis |
An observation far from the bulk of the data. A boxplot flags points more than 1.5 interquartile ranges beyond the quartiles. An outlier may be an error, or the most informative point in the sample; it is checked, not deleted by rule.
In Descriptive statistics
The five-number summary of a sample is its minimum, first quartile, median, third quartile and maximum. A boxplot draws the box from the first to the third quartile with a line at the median, and whiskers out to the most extreme data within 1.5 interquartile ranges of the box. Points beyond the whiskers are drawn individually as possible outliers.
Used in
See also
Five-number summary and boxplot · Interquartile range · Sample quantile · Range · Scatterplot · Sample variance and standard deviation · Normal quantile plot · Data table