The Essentials of Biostatistics for Physicians, Nurses, and Clinicians

3.7 Measures of the Center of a Distribution 43

Of these fi ve, we will only discuss the most common: 1, 4, and 5.
The next cartoon (Fig. 3.5 ) describes the sample mean of a data set
(this is the arithmetic mean, but when “ arithmetic ” is left off, it is
understood).
Note that the value, 38, is much larger than all the other values,
and may be considered an outlier. We have already seen that outliers
can have a large infl uence on the sample mean. If we removed 38, the
sample mean would be (5 + 7 + 3 + 7)/4 = 22/4 = 5.5.

Figure 3.5. Explanation of the sample mean (taken from the Cartoon Guide to Statistics

with permission).