Blog 6: How to summarize variation in data using Histogram?


Histograms are a type of bar chart that visualizes the distribution of numerical data. Its structure is similar to that of a bar graph. Each bar in the histogram represents a group of data, and the height of the bar represents the frequency of the data in the group. This is a powerful quality planning and management tool to help you understand precautions and corrective actions.

Histograms help clarify the frequency distribution of data from groups of samples and help identify areas of improvement in the process quickly and easily. It is a pictorial representation of data. It is the most commonly used bar graph for recording frequency distributions of data.

This tool helps categorize the frequency of your data into age, days of the week, or any other data that can be represented chronologically or numerically. The histogram is an excellent quality planning and control tool that supports us to comprehend protective and appropriate actions

Uses of Histogram:

• Histograms can be used to easily interpret a large amount of data and identify patterns

• it can also be used to make predictions of process performance

• To identify the different causes of a quality problem

• The data are numerical

• You want to see the shape of the data`s distribution, especially when determining whether the output of a process is distributed approximately normally

• Analyzing whether a process can meet the customer`s requirements

• Analyzing what the output from a supplier`s process looks like

• See whether a process change has occurred from one time period to another time period

• Determining whether the outputs of two or more processes are different.

• You wish to communicate the distribution of data quickly and easily to others

• A histogram is used to simply interpret a huge amount of data and recognize patterns.

• We can use the histogram to make predictions of the process performance.

• With the use of a histogram, we can find out the different causes of quality problems.

How to create Histograms:

Use Histogram: First, determine the process, product, or purpose for which you want to use the histogram.

Data collection: Second, start with data collection. Get 100 150 points of data, create histograms of appropriate length, and analyze the data better

Area calculation: Calculate the area by subtracting the maximum value from the minimum value of the data.

Specify the number of intervals: Specify the number of intervals to divide the range.

Dataset Summary: Summarizes data at intervals and counts the frequency of the data over a range.

Create Graph: Create a graph using the data

Chart pattern analysis: Analyze trends and extract the required data

Histograms type:

There are different types of histograms.

• Multi-peak or multi-modal

• Normal distribution

• Truncation or heart-cut histogram

• Distorted distribution

• Edge peak or bimodal

• Double Peaked Histogram

Histogram benefits

Histograms have several advantages.

• It shows a large amount of data.

• Histograms can be used to show the future performance of the process.

Disadvantages of histogram

Histograms have some drawbacks.

• Histograms can only use continuous data.

• It is more difficult to compare two datasets.

Example of Histogram:

Click on the following video and see the solved example of the histogram:

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