2.2. Common Graphs and Data Plots http://www.ck12.org
the mid-50′s) which seems to indicate that overall, these countries manufacture a smaller percentage of glass from
recycled material than they do paper. It is interesting to note in this data set that Sweden actually imports glass from
other countries for recycling, so their effective percentage is actually more than 100!
Bivariate Data: Scatterplots and Line Plots
Bivariatesimply means two variables. All our previous work was withunivariate, or single-variable data. The goal
of examining bivariate data is usually to show some sort of relationship orassociationbetween the two variables.
In the previous example, we looked at recycling rates for paper packaging and glass. It would be interesting to see
if there is a predictable relationship between the percentages of each material that a country recycles. Here is a data
table that includes both percentages.
TABLE2.20:
Country % of Paper Packaging Recycled % of Glass Packaging Recycled
Estonia 34 64
New Zealand 40 72
Poland 40 27
Cyprus 42 4
Portugal 56 39
United States 59 21
Italy 62 56
Spain 63 41
Australia 66 44
Greece 70 34
Finland 70 56
Ireland 70 55
Netherlands 70 76
Sweden 70 100
France 76 59
Germany 83 81
Austria 83 44
Belgium 83 98
Japan 98 96Figure:Paper and Glass Packaging Recycling Rates for 19 countries
Scatterplots
We will place the paper recycling rates on the horizontal axis, and the glass on the vertical axis. Next, plot a point
that shows each country’s rate of recycling for the two materials. This series of disconnected points is referred to as
ascatterplot.