• Divide the range of the data into non-overlapping classes of equal width.
• Count the number of observations in each class. This is the class frequency. Make a frequency table – a table with the number of individuals falling into each class. (Can also make a relative frequency table).
• Draw the histogram. The horizontal scale corresponds to the classes and the vertical scale to the frequency (or relative frequency). A vertical bar is drawn above each class with the bar height being the class frequency (or relative frequency).