Every value, visible
A dot plot is the simplest honest chart: a number line, with one dot stacked above its value for every observation. Nothing is binned, averaged or hidden. Small datasets keep their individuality: you see the cluster, the gaps, the lonely value at the end, and the mode as the tallest stack. Teachers love dot plots because the data stay tangible; analysts love them because nothing was summarized away.
Goals scored per match over a 20-match stretch: values from 1 to 6, with 3 scored eight times. The stack over 3 towers; the median sits at 3, the mean at 3.25. The plot shows at a glance what a summary would take a sentence to say: this team usually scores around three, dips to one now and then, and never drew a blank in this stretch. The rough symmetry around the big stack is visible, not asserted.
Dot plot, histogram, or bar chart?
Dot plots and histograms show distributions of numbers; bar charts compare categories. Between dot plot and histogram, the count decides: with a few dozen values and a modest number of distinct values, the dot plot's fidelity wins. As values multiply or spread out, stacks become skyscrapers and bins become necessary: the histogram takes over. This tool switches automatically beyond about 40 distinct values.
Breaking the one-dot-per-value rule by rounding coarsely to force stacks. Rounding to create the plot changes the data. Round only to the precision the measurements actually carry (whole goals, whole minutes), and say so.
Gaps and clusters are findings
An empty stretch of the number line inside the data's range is information: no observations fell there. Two clusters with a gap between them usually mean two groups were mixed. A dot plot is often the first chart to reveal both, because nothing was smoothed in the making.
Frequently asked questions
What is a dot plot used for?
Showing the distribution of a small dataset with every observation visible: scores, counts per day, measurements in a class. The tallest stack is the mode.
How is a dot plot different from a histogram?
A dot plot keeps individual values; a histogram bins them. Dot plots suit tens of values; histograms suit hundreds and up.
Can a dot plot have decimals?
Yes, the dots sit at their true positions on the number line. Stacking just needs repeated values, which decimals produce less often; with many distinct values a histogram serves better.