Representation of data: diagrams

Learning objectives

Choose a suitable diagram for a set of raw data and justify the choice by comparing what stem-and-leaf diagrams, box-and-whisker plots, histograms and cumulative frequency graphs show or hide

Construct and interpret stem-and-leaf diagrams, including back-to-back diagrams with a key, and read the median and quartiles from them

Draw box-and-whisker plots from the minimum, lower quartile, median, upper quartile and maximum, and use them to compare the centre and spread of two data sets

Draw and interpret histograms with unequal class widths using frequency density = frequency ÷ class width, identifying the class boundaries correctly

Draw a cumulative frequency graph and use it to estimate the median, quartiles, percentiles, interquartile range and the number or proportion of values above, below or between given values