http://www.ck12.org Chapter 5. Measures of Central Tendency
CHAPTER
(^5) Measures of Central
Tendency
Chapter Outline
5.1 Mean
5.2 UNGROUPEDDATA TOFIND THEMEAN
5.3 GROUPEDDATA TOFIND THEMEAN
5.4 Median
5.5 MEDIAN OFLARGESETS OFDATA
5.6 Mode
Introduction
Here’s an activity that will involve all the students in your class and will also serve as a learning tool to enhance your
understanding of mean, median and mode. Prior to the beginning of class, fill a pail with single, plastic interlocking
blocks similar to those shown below. You and your classmates will each use only 1 hand to gather a handful of
blocks from the pail.
Before you and your classmates begin to pick your handfuls of blocks, have a brain-storming discussion to reveal
your knowledge of the measures of central tendency. Record the various responses and refer to these as the lessons
progress.
You and your classmates can now each proceed to the pail to collect a handful of blocks. Once you have had some
time to compare your handful with those of your classmates, record each of your numbers of blocks on post-it notes.
The post-it notes for you and your classmates can now be placed in order on a large sheet of grid paper. The grid
paper allows for repeated numbers to be posted in the same column.
What do you think you would be finding if you were to determine the mean number of blocks that had been picked
from the pail? Now share your blocks with your classmates, and have your classmates do the same. so that you
each have a similar number of blocks. From this sharing process, it is very likely that 2 groups of students will be
created. One group will have stacks of one number of blocks, and another group will have stacks of another number
of blocks. You and your classmates may come to realize that further sharing will not create stacks of the same size
for each of you. Is it clearer to you now what we are talking about when we use the term mean?
Place your stacks of blocks in a safe place, for they will be used again in the discovery of the mode and the median.
The numbers that were placed on the grid paper can also be used for mathematical calculations of the mean, median,
and mode of your data.