# STAT 100 Lecture Notes - Lecture 9: Squared Deviations From The Mean, Interquartile Range, Box Plot

## Document Summary

The minimum and maximum values alone tell us little about the distribution as a whole. Likewise, the median and quartiles tell us little about the tails of a distribution. To get a quick summary of both center and spread, combine all five numbers. The five-number summary of a distribution consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation, written in order from smallest to largest. The five-number summary divides the distribution roughly into quarters. This leads to a new way to display quantitative data, the boxplot. How to make a boxplot: a central box spans the quartiles q1 and q3, a line in the box marks the median m, lines extend from the box out to the smallest and largest observations. Consider a second travel times data set, these from new york. Find the five-number summary and construct a boxplot.