Which of the boxplots in the enclosed image is skewed with an outlier?
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lizedwards | Certified Educator
In the attached image, the boxplot for Region C is both skewed and has an outlier.
In statistics, a boxplot is a way to show numerical data in their quartiles. A boxplot consists of a rectangle with two "whiskers" extending in each direction. The rectangle at the center of the boxplot represents the interquartile range (the first quartile to the third quartile). The line inside of the rectangle represents the median. The whiskers on either side of the rectangle can represent different things, but commonly represent the minimum and maximum.
A boxplot is skewed if the data set is not symmetric. A simpler way to understand the concept of a skewed boxplot is to think of slicing the box down the middle. Are the two halves roughly mirror images of each other? If they are, the boxplot is symmetric. If the two halves are not mirror images of each other, the boxplot is skewed.
Outliers in statistics are simply points of data that are distant from other observations. In a boxplot, outliers are shown by floating points that are linearly plotted alongside the box and whiskers.
Knowing the definitions above, we can refer back to the attached image, and define the following properties for the data in boxplot C:
- It is skewed because the box portion of the graph is asymmetrical.
- It has an outlier because there is a point floating outside the box and whiskers on the right side.