ABSTRACT
Graphical displays are often used to summarize data and usually help to uncover special characteristics of the data set. Histograms and stem-and-leaf plots are examples of graphical displays of data. The stem-and-leaf plots are particularly helpful in visualizing the median or middle value in data, the range or spread of data (distance between the lowest and highest data values), and quartiles (the first quartile is a score that separates the bottom 25% of the data in a frequency distribution from the other data and the third quartile is a score that separates the top 25% of the data in a frequency distribution from the other data). The inter-quartile range is the distance between the first and third quartile scores. It measures the range of scores in the middle 50% of the frequency distribution.
