What is a histogram?

• A. A graph of vertical bars representing the frequency distribution of a set of data.
• B. A line chart showing trends over time.
• C. A pie chart showing proportions.
• D. A scatter plot of data points.

Answer: (A)

A histogram is a graph that shows the distribution of a single variable by grouping data into consecutive intervals, called bins, and displaying how many observations fall into each bin with vertical bars. The height of each bar represents frequency (or relative frequency), and the bars typically touch to reflect the data as a continuous range. This setup lets you see the overall shape of the data—the spread, skewness, and whether there are one or several peaks (modes).

Other charts describe different things: a line chart tracks changes over time, a pie chart breaks a whole into proportional slices, and a scatter plot shows relationships between two variables. None of those focus on the frequency distribution of a single variable in consecutive intervals like a histogram does.