Exploring Histograms
To use this interactive data analysis tool:
- Entering and editing data: Enter data by clicking in the Data Input box; type the value and press enter on the keyboard. To edit data, select a data value by clicking on it and either delete the value or enter a new one. You can order your data values by checking the Order Data box. Use the slider to change the length of the intervals used to create the histogram.
- Looking at the histogram: When you click on a particular bar on the histogram, the percentage of data values represented by that bar is displayed. Place the mouse cursor along the bottom axis to reveal the values determining the endpoints of each interval.
- Summary statistics: In the Summary Statistics box, the length of the intervals, the number of data points, as well as the mean, median, and the standard deviation are displayed.
Below the interactive tool are two sample activities that students could use to explore with and learn about statistics using this interactive tool.
Sample Activity 1
- Clear any previous data.
- Enter the numbers 2,3, 4,4 and 5 into bar chart.
- Note the summary statistics. What is the value of the mean? The median?
- Describe the shape of the histogram. Which of the following is easily "seen" on the histogram: mean, median, or mode?
- Now enter 77.
- What happened to the mean? To the median? To the mode?
- How does the histogram change?
- What happens to the shape of the bar chart if you change the width of the bars?
Sample Activity 2
- Clear any previous data.
- Enter the numbers 2, 3, 4, 4 and 5 using Data Input.
- Note the summary statistics. What is the value of the mean? The median?
- Describe the shape of the histogram. What is the value of the mode?
- Now repeatedly enter the number 5.
- What happened to the mean? To the median? To the mode?
- How does the histogram change?
- What happens to the shape of the histogram if you change the length of the intervals?