Construct back-to-back stem-and-leaf plots and histograms and describe data, using terms including 'skewed', 'symmetric' and 'bi modal' (ACMSP282)
Source: Australian Curriculum, Assessment and Reporting Authority (ACARA)
Numerical data (quantitative data) consists of values in which there is a definite numerical order, for example, scores in a test or heights of students in a class.
A stem-and-leaf plot can be used to represent numerical data.
A stem-and-leaf plot represents the values of the data set in the form of a stem and a leaf.
The stem is the first digit of a two-digit number, or the first two digits of a three-digit-number, and so on.
The leaf is usually the last digit of the value.
The marks out of 50 obtained by 16 students in a Mathematics test are:
Represent this information on a stem-and-leaf plot.
We use the first digit of each mark as the stem, writing 7 as 07.
|1||1 4 4 7 9 9|
|2||4 5 7 9 9|
|4||3 9||3\(\mid\)2 represents a mark of 32|
We can see that stem-and-leaf plots are useful for displaying the shape of the data and giving the reader a quick overview. They retain most of the raw numerical data and are useful for highlighting outliers and finding the mode.