Box and whisker plots

BOX AND WHISKER PLOTS

Presented by-Dr Garima Gupta

Post Graduate ResidentUniversity College of Medical Sciences and GTB Hospital

INTRODUCTION• A Box-and-Whisker Plot shows the distribution of a set of data along a

number line, dividing the data into four parts using the median and quartiles.• It was introduced by John Tukey in 1969, Hence also known as Tukey

Boxplot.• It is also called as Five number summary box, as it consists of the

median, the quartiles (lower quartile and upper quartile), and the smallest and greatest values in the distribution.

How to construct a Box And Whisker Plot • For instance we have a data set of 15 values for HDL-Cholesterol 31, 41, 44, 46, 47, 48, 49, 52, 53, 54, 57, 58, 60, 62, 65 (arranged in

ascending order)

Find the median of data 31, 41, 44, 46, 47, 48, 49, 52, 53, 54, 57, 58, 60, 62, 65

Median = Q2

Find the medians of the two halves 31, 41, 44, 46, 47, 48, 49, 52, 53, 54, 57, 58, 60, 62, 65

Lower Median / Q1 Upper Median / Q3

Draw a number line that extends far enough in both directions to include all the numbers in your data . (Vertically)

Thank You