What Is Histogram Plotting?

Histogram plotting in statistics is the use of a graph to show probability distribution and to estimate normal values of that distribution with a given variable. This plotting is done in bar-graph format, and the information may be normalized to account for data-gathering errors. The histogram is normally organized to show the frequency of the variable on the left and the variable on the bottom. Creating a histogram manually is generally easy, unless a large amount of data is captured; in this case, mathematical and spreadsheet programs can turn the data into a histogram. When the histogram is made, there may be several bars that are the same size; if this happens then the bars are connected.

Every histogram is created as a bar graph and is made to estimate how many times a variable will occur. While histogram plotting will use the same style of graph over and over, a histogram can be used for many different categories, such as building height, plane arrivals per minute or the number of different chairs in a furniture store or warehouse. Along with displaying the frequency of a variable, a histogram is commonly normalized using an algorithm. Normalization is when the data is changed, according to the algorithm, to account for potential errors during information collecting, and it tends to make the graph more realistic.

Along with using a bar graph, histogram plotting organizes the graph in a standard way. On the left side of the histogram, often labeled as frequency, the user can check the number of times the variable occurred. The bottom portion of the histogram displays the variable itself. For example, if the variable is building height, the bottom section will display different height figures, and the bars would ascend based on how many buildings were found during data collection.

Performing histogram plotting with a small amount of data is easy and can be done manually; however, this becomes difficult when hundreds or thousands of records are captured. This results in most histograms being created by math and spreadsheet software. These programs take the data and automatically arrange it into a histogram.

When histogram plotting is performed, most adjacent bars will not be the same height, because the frequency will be different for the variable. If the frequency is the same for several bars in a row, these bars are typically connected and turned into one very wide bar. This makes it easier to look at the histogram and easier to create, especially if the wide bar spans a large area of the histogram.