There are two characteristics of a group of data that we will concern ourselves with in this
text. The first characteristic answers the question, "do the data tend to cluster or group around
some particular value or values?"
This first characteristic is CENTRAL TENDENCY. The three MEASURES OF CENTRAL
TENDENCY, discussed in the following pages, are used to identify the value around which the
data tend to cluster.
The second characteristic answers the question, "do the observations cluster very tightly
around the measure of central tendency, or, are they spread out?" The second characteristic is
called DISPERSION. Two measures of dispersion will be discussed in this text.
What are the two characteristics of a group of data that we concern ourselves with in this