Graphs are useful because they allow the observer to make inferences
about data at a glance. They are easier to read than tables of data,
and they make it much easier to spot trends. Thus, it is important to
understand how to make and read graphs of data.
There are many different kinds of graphs, and most of them rely on
knowledge of certain statistics, such as the mean, median,
mode, and range. The first section deals with the meaning of
these statistics and how to find them, given a set of data.
The second section deals with a specific type of graph--the
histogram. The histogram is the graph most often used to show
distribution of values. This section explains how to make a
frequency distribution table from a set of data, and how to make a
histogram from a frequency distribution table.
Although this chapter only deals with one type of graph, it provides
the tools needed to make other types of graphs; namely, it explains
how to find certain statistics. In future math or statistics classes,
you will use these statistics to make other types of graphs. These
statistics are also useful to learn because they are frequently
mentioned in reports, on the news, in commercials, etc. By learning
how to compute the mean, median, mode, and range of a set of data, you
will better understand statistics provided by other sources.
Learning how to make a histogram is also useful. If you ever need to
present data in a report, a histogram will make it much easier to
understand and more aesthetically pleasing.