Illuminations: Histogram Tool

Histogram Tool
This tool can be used to create a histogram for analyzing the distribution of a data set using data that you enter or using pre‑loaded data that you select.

Instructions
 
At the top of the screen, choose one of the sets of data from Select a Data Set. A histogram will be generated automatically based on the data you select.

The Show Frequency Table button displays a frequency table based on the histogram.

The interval size can be changed by dragging the slider below the histogram. Alternatively, change the value in the Interval Size box, and then click Update Histogram.

The minimum, maximum, and a description can be entered, but the Update Histogram button must be pressed for any changes to take effect.

Press the Clear button to remove all data from the form at the bottom of the screen. Enter new data—one per line—by typing numbers into the form. At least two values must be entered, or a histogram will not be generated. When you've entered all data values, press the Update Histogram button.

Exploration
 
Choose one of the pre‑loaded data sets from the drop‑down menu.
  • Move the slider below the histogram all the way to the right. Then, move the slider all the way to the left. What happens? If there are too few bars in the histogram, the data appears to be clumped in the middle. And if there are too many bars, it becomes difficult to notice trends. About how many bars should you use to display a set of data?
  • Change the value for Minimum Frequency so that it equals roughly half the Maximum Frequency, and then press Update Histogram. How does this change the display of data?
  • As you've seen, the same data can be represented in more than one way, and the way it is represented can lead to different interpretations. Can you adjust the number of bars and the minimum and maximum frequency to lead to two different interpretations of the same data?

  

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