Let's Put the Mode to the Test

As you saw in the dice game, the mode is a measure of the statistic that occurs most often. In that example, you could think of each point as an "occurrence" of the student.

Now look at this sample set of test scores (if you have access to Excel 3.0, you may download this in spreadsheet form):

91, 98, 87, 76, 100, 45, 72, 85, 92, 88, 87, 90, 91, 66, 100, 99, 67, 85, 79, 80, 85

To get a better look at these scores, we put them in descending order:

100, 100, 99, 98, 92, 91, 91, 90, 88, 87, 87, 85, 85, 85, 80, 79, 76, 72, 67, 66, 45

Even in this ordered fashion, these data are hard to read. Let's put them in a stem and leaf diagram:

STEM	LEAF
4	5
5
6	6 7
7	2 6 9
8	0 5 5 5 7 7 8
9	0 1 1 2 8 9
10	0 0

What is the mode of this set? Here, we are asking, "Which scores occur the most often?"

Now, draw a frequency histogram of this information. How does your grouping of scores affect the histogram?

Why do we want to know this statistic? What possible use could we have for the mode? What information does the mode provide? Take a while to discuss this with your group and class.

After your discussion, please continue to the next page.

Return to title page.

send comments and questions to Jay Hill