— notes — 2 min read
categorical data. Each category in the frequency distribution is represented by a bar or rectangle of equal width, and the picture is constructed in such a way that the height of each bar is proportional to the corresponding frequency or relative frequency.
numerical data when the data set is
reasonably small. Each observation is represented by a dot above the location corresponding to its value on a horizontal measurement scale. When a value occurs more than once, there is a dot for each occurrence and these dots are stacked vertically.