Transcript Graphs that Enlighten and Graphs that Deceive

Graphs that
Enlighten and
Graphs that Deceive
Chapter 2 Section 4
Types of Graphs
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Scatter plot (Scatter Diagram)
Time Series Graph
Dot plots
Stem-plots
Bar Graphs
Pareto
Pie Charts
Frequency Polygons
Ogive
Pictographs
Graphs That
Enlighten
Scatter Plot
A scatter plot is a plot of
paired (x, y) quantitative
data with horizontal xaxis and vertical y-axis.
used when there is a
correlation between the
variables.
Time Series Graph
A time-series graph ia a
graph of time series data,
which are quantitative
data that have been
collected over different
points in time, such as
monthly or yearly.
Dot-plots
A dotplot consists of a
graph in which each data
value is plotted as a point
(or dot) along a horizontal
scale of values. Dots
representing equal values
are stacked.
Stem-plots
A stemplot (or Stem-andleaf plot) represents
quantitative data by
separating each value into
two parts: the stem (such as
the leftmost digit) and the
leaf (such as the rightmost
digit).
Bar Graphs
A bar graph uses bars
of equal width to show
frequencies of
categories of
Categorical (or
Qualitative) data.
Pareto Graphs
This is similar to a Bar
Graph, but there is
one
stipulation/condition
the data be arranged
in descending order.
Pie Graph
A pie chart is a graph
that depicts categorical
data as slices of a
circle, in which the size
of each slice is
proportional to the
frequency count for
each category.
Frequency Polygon
Frequency polygons
are similar to
histograms but they
use line segments and
have points plotted at
the class midpoints.
Ogive
An ogive (pronounced
“oh-jive”) is a line
cummulative line
graph or frequency
polygon.
Graphs That
Deceive
Non-Zero Axis
Always examine a
graph to see whether
an axis begins at
some point other than
zero so that
differences are
exaggerated.
Pictographs
When examining data
depicted with a pictograph,
determine whether the
graph is misleading
because objects of area or
volume are used to depict
amounts that are actually
one-dimensional.
Conclusion
• Describe – Graphs should be descriptive.
• Explore – Look for features that are useful in
the graph.
• Compare – Make several different graphs
and compare the results.