How do you determine the class interval from a histogram?

To determine the class interval from a histogram, measure the width of each bar on the x-axis.

In a histogram, the x-axis represents the range of data values, divided into intervals known as class intervals or bins. Each bar in the histogram corresponds to a class interval, and its height shows the frequency of data points within that interval. To find the class interval, look at the range of values covered by one bar. For example, if one bar starts at 10 and ends at 20, the class interval is 10 units wide.

To ensure accuracy, check the scale of the x-axis. Sometimes, the axis might be labelled in increments, such as 0, 5, 10, 15, etc. In this case, if a bar spans from 10 to 20, the class interval is still 10 units. If the histogram uses different scales or if the intervals are not uniform, you may need to measure each interval separately.

Understanding class intervals is crucial for interpreting histograms correctly. They help you see how data is distributed across different ranges, making it easier to identify patterns, trends, and outliers. When analysing a histogram, always pay attention to the class intervals to ensure you accurately understand the data being presented.