Question

7. What is a box plot and what does it display?

Answer 1

A Box Plot is the visual representation of the statistical five number summary of a given data set.

A Five Number Summary includes:

• Minimum
• First Quartile
• Median (Second Quartile)
• Third Quartile
• Maximum

It is a graph that gives you a good indication of how the values in the data are spread out. They are useful for identifying outliers and for comparing distributions.

In a box and whisker plot:

• the ends of the box are the upper and lower quartiles, so the box spans the interquartile range
• the median is marked by a vertical line inside the box
• the whiskers are the two lines outside the box that extend to the highest and lowest observations.

Typical Boxplot looks like :