Boxplot vs Dotplot
Both terms below come up in the same part of the course, and students mix them up. Here is each one defined on its own, side by side, so you can see where they part company.
Boxplot
Graphs and displays
A boxplot is a graph of the five-number summary, with a box from Q1 to Q3, a line at the median, and whiskers to the extremes.
A boxplot turns the five-number summary into a picture: a box spans (the first quartile) to (the third quartile), a line inside marks the median, and whiskers reach the smallest and largest non-outlier values. For example, a longer right whisker signals a right-skewed distribution. Points more than beyond the nearer quartile are drawn separately as outliers. Boxplots make it easy to compare center and spread across several groups side by side.
Dotplot
Graphs and displays
A dotplot displays quantitative data by stacking one dot above a number line for each observation at its value.
A dotplot places every data value as a dot over its position on a number line, stacking repeats. For example, the values 3, 3, 4, and 6 would show two dots above 3 and one dot each above 4 and 6. Because each dot is one observation, you can read off the shape, center, and any gaps or outliers directly. Dotplots work best for small data sets.