For the graph to represent your data most effectively, consider the following guidelines.
The sample size should be less than approximately 50
A dotplot is best when the sample size is less than approximately 50. If the sample size is 50 or greater, a dot may represent more than one observation. Consider using a boxplot or a histogram in addition to the dotplot so that you can more easily identify primary characteristics of the distribution.
The sample data should be selected randomly
In statistics, random samples are used to make generalizations, or inferences, about a population. If your data were not collected randomly, your results may not represent the population.
