Key Terms

3D visualization

a graph or display that shows information plotted along three dimensions, typically referred to as the x-axis, y-axis, and z-axis

bar graph

a chart that presents categorical data in a summarized form based on frequency or relative frequency

bin

an interval or range into which data points are grouped; often used to create histograms

binomial distribution

a probability distribution for discrete random variables where there are only two possible outcomes of an experiment

bivariate data

paired data in which each value of one variable is paired with a value of a second variable

boxplot (“box-and-whisker plot”)

a graphical display showing the five-number summary for a dataset: the min, first quartile, median, third quartile, and the max

choropleth graph

a graphical display where areas are shaded in proportion to the value of a variable being represented; choropleth maps are typically used to present spatial patterns in geographic regions

correlation heatmap

a visual representation of the correlation matrix that implements color coding to visualize those variables with stronger correlations and those variables with weaker correlations.

data visualization

the use of graphical displays, such as bar charts, histograms, and scatterplots, to help interpret patterns and trends in a dataset

discrete random variable

a random variable where there is only a finite number of values that the variable can take on

five-number summary

a summary of a dataset that includes the minimum, first quartile, median, third quartile, and maximum

geospatial data

data that describes the geographic location, shape, size, and other attributes relative to a location on the Earth's surface

Geospatial Information System (GIS) mapping

a tool for visualizing, analyzing, and interpreting spatial data that makes use of various types of geographical data, such as maps and satellite images

grid heatmap

a graphical representation of data where values are depicted as colors within a grid such as an (x, y) mapping; a grid heatmap is typically used to show correlations between two quantities

histogram

a graphical display of continuous data showing class intervals on the horizontal axis and frequency or relative frequency on the vertical axis

interquartile range (IQR)

a number that indicates the spread of the middle half, or middle 50%, of the data; the difference between the third quartile ($Q_3$) and the first quartile ($Q_1$)

line chart

a type of graph that uses lines to connect $(x,y)$ data points

median

the middle value in an ordered dataset

normal distribution

a bell-shaped distribution curve that is used to model many measurements, including IQ scores, salaries, heights, weights, blood pressures, etc.

outliers

data values that are significantly different from the other data values in a dataset

Pareto chart

a type of bar chart where the bars are arranged in order of decreasing height

Poisson distribution

a probability distribution for discrete random variables used to calculate probabilities for a certain number of successes in a specific interval

quartiles

numbers that divide an ordered dataset into quarters; the second quartile is the same as the median

scatterplot (or scatter diagram)

a graphical display that shows the relationship between a dependent variable and an independent variable

spatial heatmap

a data visualization method used to represent the density or intensity of data points within a geographical area using coloring and shading to represent densities of various attributes

univariate data

observations recorded for a single characteristic or attribute