Displaying Your Statistical Data with Charts and Graphs - dummies

# Displaying Your Statistical Data with Charts and Graphs

You can summarize your statistical data in a visual way using charts and graphs. These are displays that are organized to give you a big picture of the data in a flash and to zoom in on a particular result that was found. In this world of quick information and sound bites, graphs and charts are commonplace.

Here are some popular types of graphs and charts:

• Some of the basic graphs used for categorical data include pie charts and bar graphs, which break down how many responses were given for each group of certain variables, such as gender or which applications are used on teens’ cellphones.

An example of a bar graph

The above bar graph shows the results of a survey that asked respondents about their pet peeves at work. Because there were multiple responses, the bar graph was a good choice for displaying this information. A bar graph would also be useful for displaying people’s opinions on a particular issue, where the bars might be labeled in order from “Strongly Disagree” up through “Strongly Agree.”

• For numerical data such as height, weight, time, or amount, different types of graphs are needed.

An example of a histogram

Graphs called histograms and boxplots are used to summarize numerical data, and they can be very informative, providing excellent on-the-spot information about a data set. The above histogram shows the time between eruptions of the Old Faithful geyser.

An example of a boxplot

This boxplot shows the age of the Best Actress Award winners from 1928 to 2009.

You’re going to run across charts and graphs every day — you can open a newspaper and probably find several graphs without even looking hard. Having a statistician’s magnifying glass to help you interpret the information is critical so that you can spot misleading graphs before drawing the wrong conclusions and possibly acting on them.