Lorenz Curve

http://www.ssc.ca/en/education/archived-case-studies/case-studies-for-the-2003-annual-meeting-neighbourhood-factors-and-children
A Lorenz Curve, or accumulative line graph, is used to compare actual dispersion of an entity (typically wealth) to how it would be if the entity were distributed evenly or equally amongst the subjects. Thus, it illustrates inequality well. This Lorenz Curve illustrates the unequal distribution of cumulative income. The downward bending indicates low portion of the population attaining high amounts of the wealth. These graphs are useful for economists and policy makers when it comes to salary etc.

Similarity Plots

http://www.jbaas.com/HTML/Previous%20Issues/Volume%20No.%202%20No.%202/Headings/H-7.html

Similarity grids are visualization tools used to compare likeness between two differing entities. Using a color gradient to represent high-to-low similarity, it becomes simple to see how alike the two observations in question are. This matrix compares the phenotypes of ten different bacterial strains. The scale on the right indicates percent similarity between each strain. For example, strain 7 is from 30-39 % similar to strain 3.

Box Plot

http://grasswiki.osgeo.org/wiki/R_statistics
Box plots can be very useful when comparing multiple sets of data. They provide a simple summary of dispersion and show means of center as well (average and median). Each box plot separates its data into percentiles, usually noting 25th, 50th (center), and 75th quartiles as the three horizontal lines making up the box. These box plots are representations of geologic types at differing elevations. Each type of rock (and a mixture of a couple of types) has its own box plot. From this study, one can see that the 50th percentile of metamorphic rocks occurred just above 1600 ft, while the 50th AND 75th percentile of sand occurred just below 1200 ft.

Population Profile

http://www.scalloway.org.uk/popu4.htm
When profiling a population, often a population pyramid is used to display the frequency (in intervals) of ages, men and women, from any particular region. They look like vertical, back-to-back histograms. This population pyramid is a generalized example of a population dispersion one might find analyzing at a typical developing country. The wide bases indicate that the majority of the population are children, from new born babies or infants to four-year-old's. Only about 8% of the entire population consists of males and females between the ages of 25 and 29.

Scatterplot

http://www.cawcr.gov.au/projects/verification/
A scatter plot is a graph that plots points "scattered" amongst a Cartesian plain. Their values are assigned by a predictor variable and response variable. If the points are closely correlated enough, a trend line may be appointed for averaging out and purposes of analyzing the trend of the data. For example, this graph shows 10 observed temperatures in degrees Celsius and compares it to the forecast temperatures for the days. The response variable points (y) did show a trend in correlation to the predictor variable (x), so the trend line was drawn. Here there is a positive correlation between observed and forecast temperatures.

Climograph

https://sites.google.com/site/comparingclimates/
A climograph represents and compares monthly temperatures and precipitation in a year to help more accurately determine an area's average climate. This is a climograph of Singapore. The bars represent cumulation of rainfall each month in cm and the dotted line represents monthly temperature averages in degrees Celsius. 

Choropleth Map: Bivariate

http://www.personal.psu.edu/faculty/c/a/cab38/GEOG321/14_multivariate02/multivariate.html
A bivariate choropleth map represents areal data from observations with two variables each instead of just one (univariate). This map of the United States is bivariate because the study monitored observations with two variables: people per square mile in 1990 and the percent change in population from then to 2000. This allows the reader to compare the population for the two years as well as understand the trend of the population change.