Common Errors in Statistics (and How to Avoid Them), 4th Edition

SUMMARY

• Examine the data and results to determine the number of dimensions in the information to be illustrated. Limit your graphic to that many dimensions.
• Limit the axes to exactly (or closely) match the range of data in the presentation unless a zero axis limit admits desired relative comparisons of the depicted values.
• Do not connect points in a scatterplot unless there is an underlying interpolation that makes scientific sense.
• Recognize that readers of your reports will copy tables and figures for their own use. Ensure that you are not misquoted by completely describing your graphics and tables in the associated legends. Do not skimp on these descriptions or you will force readers to scan the entire document for needed explanations.
• If readers are to accurately compare two different graphics for values (instead of shapes or predominant placement of outcomes), use the same axis ranges on the two plots.
• Use pie charts only when there are a small number of categories and the sum of the categorical values has scientific meaning.
• Tables are text-based graphics. Therefore, the rules governing organization and scientific presentation of graphics should be honored for the tables that we present. Headings should be differentiated from data entries by font weight or color change. Refrain from introducing multiple fonts in the tables and instead use one font and denote differences by varying weight (boldness), style (italics), and size.
• Numeric entries in tables should be in the same ...