How to Make a Histogram by Hand

A histogram looks very similar to a bar graph, except that the bars are drawn touching one another rather than spaced apart. This is to represent that the data is continuous; that is, if two adjacent bars are labelled "50 in." and "51 in.," there is a number between them, 50.5 in. With a bar graph, this is not the case; two adjacent bars might be labelled "Arizona" and "California," where there is no logical halfway-in-between value.

Things You'll Need

  • Graph paper (optional)
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Instructions

    • 1

      Divide your data into reasonably sized ranges. For example, if you were measuring people's heights and you had someone as short as 4'10" and someone as tall as 6'8", it might be reasonable to divide this 22" range up into 11 blocks of 2" each.

    • 2

      List the various data ranges you will use; in the height example, these would be 58" - 59", 60" - 61", and so on. Next to each range, tally the number of data points that fall into that range. That is, if there were four people in the 60" - 61" range, you would put 4 next to that range.

    • 3

      Draw a horizontal and vertical axis in the positive direction (right and up from the origin, respectively). Label the vertical axis "Frequency," and write values for the units. For small data samples, you will probably use each whole number going up the line 0, 1, 2, ... until you reach your maximum frequency. For very large data sets, you may have to condense this a little, such as 0, 5, 10, ... to save room. Label the horizontal axis with the number from your range categories, and write the variable measured followed by the units in parentheses below. (Example: Height (inches))

    • 4

      Draw a bar for each range category showing its tallied frequency by raising it to the appropriate height shown on the frequency axis. Make sure the bars all touch one another on their sides.

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