Geology Reference
In-Depth Information
observed in different rock samples, scientists can organize and compare the pat-
terns in the data using simple arithmetic.
Some people find statistics intimidating because they seem like complicated mathemat-
ical formulas. But really, statistical methods are simple mathematics combined in a step-
by-step sequence to uncover patterns in the data. Some statistics determine if two sets
of data have overall similarities or differences. Others determine which variables are
most important in creating the observed outcomes.
Another reason scientists organize and describe their data quantitatively is so that they
can display it using graphs. Many different types of graphs are used, and a scientist
must determine which type of graph best displays the data in an understandable way.
The most suitable graph depends on what type of data is being displayed. Figure 2-1 il-
lustrates a few common graph types used in earth science:
Pie graph:
This type of graph is best used for illustrating different pieces of a
whole. The total of a pie chart must always add up to 100 percent.
Bar graph:
Also called
histograms,
bar charts are used to display information that
can be sorted into different categories.
Scatterplot:
Scatterplot graphs illustrate how two types of data are related. Some-
times a scientist will use a scatterplot to look for patterns of relationship between
the data types — by finding clusters of data points.
Line graph:
This type of graph is most commonly used to plot changes in a type of
data over time, distance, or other variable.
Figure 2-1:
a) Pie
graph; b) Bar
graph; c) Line
graph; d) Scatter-
plot.
