A Stem and Leaf Plot Maker:

A Stem and Leaf Plot Maker:

Stem and Leaf Plot Maker


Stem and leaf plots are a great way to visualize data. This data visualization tool makes it easy to create professional-looking charts and graphs in seconds. All you need are three numbers. The tool will ask what you would like the axes of your graph to be and give you some default values to get started.


In statistics, data is represented in tables, charts, and graphs. One disadvantage of representing data in these ways is that the actual data values are often not retained. One way to ensure that the data values are kept intact is to graph the values in a stem-and-leaf plot. A stem-and-leaf plot is a method of organizing the data that includes sorting the data and graphing it at the same time. This type of graph uses a stem as the leading part of a data value and a leaf as the remaining part of the value. The result is a graph that displays the sorted data in groups, or classes. A stem-and-leaf plot is used most when the number of data values is large, and it allows you to easily calculate the mode and the median of a data set.The main advantage of a stem and leaf plot is that the data are grouped and all the original data are shown, too. In Example 3 on battery life in the Frequency distribution tables section, the table shows that two observations occurred in the interval from 360 to 369 minutes. However, the table does not tell you what those actual observations are. A stem and leaf plot would show that information. Without a stem and leaf plot, the two values (363 and 369) can only be found by searching through all the original data—a tedious task when you have lots of data!The organization of this stem and leaf plot does not give much information about the data. With only one stem, the leaves are overcrowded. If the leaves become too crowded, then it might be useful to split each stem into two or more components. Thus, an interval 0–9 can be split into two intervals of 0–4 and 5–9. Similarly, a 0–9 stem could be split into five intervals: 0–1, 2–3, 4–5, 6–7 and 8–9.

One simple graph, the stem-and-leaf graph or stemplot, comes from the field of exploratory data analysis. It is a good choice when the data sets are small. To create the plot, divide each observation of data into a stem and a leaf. The leaf consists of a final significant digit. For example, 23 has stem two and leaf three. The number 432 has stem 43 and leaf two. Likewise, the number 5,432 has stem 543 and leaf two. The decimal 9.3 has stem nine and leaf three. Write the stems in a vertical line from smallest to largest. Draw a vertical line to the right of the stems. Then write the leaves in increasing order next to their corresponding stem. A stem-and-leaf plot is a way to plot data and look at the distribution. In a stem-and-leaf plot, all data values within a class are visible. The advantage in a stem-and-leaf plot is that all values are listed, unlike a histogram, which gives classes of data values. A line graph is often used to represent a set of data values in which a quantity varies with time. These graphs are useful for finding trends. That is, finding a general pattern in data sets including temperature, sales, employment, company profit or cost over a period of time. A bar graph is a chart that uses either horizontal or vertical bars to show comparisons among categories. One axis of the chart shows the specific categories being compared, and the other axis represents a discrete value. Some bar graphs present bars clustered in groups of more than one (grouped bar graphs), and others show the bars divided into subparts to show cumulative effect (stacked bar graphs). Bar graphs are especially useful when categorical data is being used. (Source: opentextbc.ca)



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