SUMMARY STATISTICS
Tables, graphs, and other visual depictions of information are very helpful in quickly
understanding experimental results.
In addition to these methods, there is one important method
of portraying information that we will look at in more depth—the histogram.
Common Mathematical Terms
Before discussing the histogram itself, there are a few terms that are important to review that
apply to distributions.
Mean
– refers to the arithmetic average of a set of values.
Commonly, the mean is called
the average.
The mean is calculated by adding all the values together and dividing by the
number of values.
Median
– refers to the middle value of a set of data.
For example, the three numbers 4, 5,
and 6 have a median of 5.
When finding the median it is important to put the values in
numerical order.
For example, 6, 4, and 5 still have a median of 5 because it is the
middle number.
If there are an even number of values, such that there is no middle value,
the average of the two middle values is taken as the median.
For example, 3, 4, 5, and 8
have a median of 4.5.
Mode
– refers to the most common value in a set of data.
For example, 2, 2, 3, 4, and 5
have a mode of 2 because it occurs the most.
If two numbers occur with the same
frequency, there will be two modes.
Histograms