What data visualization technique is specifically useful for showing frequencies of continuous variables?

A histogram is particularly effective for displaying frequencies of continuous variables because it represents the distribution of data over specified intervals, known as bins. Each bin corresponds to a range of values and its height reflects the frequency of data points within that range. This allows for easy identification of patterns such as skewness, modality (the number of peaks), and the overall shape of the distribution.

Unlike bar charts, which are better suited for categorical data, or pie charts, which illustrate proportions of a whole, histograms specifically address the characteristics of continuous data by capturing the range of values and the frequency with which they occur. Line graphs, while useful in showing trends over time for continuous variables, do not provide insight into frequency distributions in the same way that histograms do. Thus, the histogram is the most appropriate and informative visualization technique for representing the frequencies of continuous variables.