# Histogram

A graphical display showing the distribution of data values in a sample by dividing the range of the data into non-overlapping intervals and counting the number of values which fall into each interval. These counts are called frequencies. Bars are plotted with height proportional to the frequencies.

### Class Boundary

A point that is the left endpoint of one class interval, and the right endpoint of another class interval.

### Class Interval

In plotting a histogram, one starts by dividing the range of all values into non-overlapping intervals, called class intervals, in such a way that every piece of data is contained in some class interval.

### End Point Convention

In histograms, you need to decide where to count values that are on the exact boundary between two intervals: either in the left or in the right interval. You should always let readers of the histogram know which side is chosen.

**See also: **Cumulative Frequency, Frequency Distribution, Relative Frequency.

**Subjects: ** Statistics