Histogram Example: Hello, Readers! Here we will discuss two important industrial examples to prepare a Histogram and its interpretation. If you are interested in downloading the Excel template/format, then go through the beneath links.
A Process engineer of an organization (XYZ Ltd) had decided to know the bins range [frequency distribution] of pouring temperature of casting and he has started collecting the data of 30 number readings and analyzing that data distribution that histogram graph is normal or non-normal. Illustrations of the same readings are given below,
Interpretation of Result: Non-normal
data distribution.
Example-2:
We have collected the 30 readings of green sand permeability, details are given below and also, and we have plotted a histogram to know the data frequency distribution.
Shanti Gopal Pradhan is an experienced professional in Quality Management Systems, QA, Operations, Business Excellence, and Process Improvement. He has strong expertise in international standards including IATF 16949, ISO 9001, ISO 14001, ISO 45001, and ISO 17025, along with methodologies such as TQM, TPM, and Six Sigma.
He holds a degree in Mechanical Engineering along with an MBA, combining strong technical acumen with strategic business insight, he is a Certified Internal Auditor, Lead Auditor, and Six Sigma Black Belt, with a proven track record in driving quality transformation and operational excellence.
The 7QC Tools (Also Known as “Seven Basic Tools of Quality”) originated in Japan. First emphasized by Kaoru Ishikawa, a professor of engineering at Tokyo University and the father of “quality circles”. These tools are used to solve critical quality-related issues. You can use the 7 basic tools of quality to help understand and solve problems or defects in any industry. With the help of Excel, you can plot the graphs / Diagrams to resolve the daily quality problems. I will help you to understand the basic ideas and knowledge of 7QC Tools and their usage.
For solving problems seven QC tools are used Pareto Chart, Cause & Effect Diagram, Histogram, Control Charts, Scatter Diagrams, Graphs/Process Flow Diagram, and Check Sheets. All these tools are important tools used widely in the manufacturing field to monitor the overall operation and continuous process improvement. seven QC tools are used to find out the Root cause of the problem and implement the action plan to improve the process efficiency.
Enhances customer satisfaction through improved quality product
Reduce cycle time and improve efficiency
Control cost of poor quality / Cost of quality
Reduce defects and optimize the production
Reduce variations and improve the quality of Products
Encouragement of teamwork and confidence
Enhancement of customer focus.
Pareto Chart:-
A Pareto Chart is named after the Italian Economist Vilfredo Pareto. It is a type of chart that contains both bars and a line graph, where the individual values are represented in the bar graph in descending order (largest to smallest value) and the cumulative percentage is represented in the line graph.
Click here to learn “How to Plot Pareto Chart In Excel”.
Understanding the Pareto Chart principle (The 80/20 rule):
The Pareto principle is also known as the 80/20 rule derived from the Italian Economist Vilfredo,
The principle is understood as –
20% of the input creates 80% of the results
Or
80 % of the effects come from 20% of the causes.
Pareto Chart Example
[Figure-1]
In the above Pareto Chart[Figure-1], we can see the cumulative% in the line graph, According to the Pareto Chart principle 80/20 rule, the 80% cumulative in the line graph is filling under the low hardness, which means BH, Damage, SH and Low hardness defers are coving the 80% of contribution over total types of defects. And those 80 % of contributions were due to the 20% caused.
Histogram:-
The histogram is one of the 7QC tools, which is the most commonly used graph to show frequency distribution.
Helps summarize data from a process that has been collected over a period of time.
Click here to know the “How to Plot Histogram in Excel:
Histogram Template
[Figure-2]
Fish-bone Diagram/Cause and Effects /Ishikawa Diagram:-
The cause and Effects Diagram looks like a fish that’s why it’s called Fish-bone Diagram, also called the Ishikawa diagram.
It’s a visualization tool for categorizing the potential causes of a problem in order to identify its root causes.
CFT members are identifying the potential cause through the Brainstorming process of individuals and together.
The Potential cause is related w.r.t below as
Machine
Manpower
Environment
Method
Materials
Measurement
[Figure-3]
Scatter diagram:-
The scatter diagram graphs pairs of variable data, with one variable on each axis, to look for a relationship between them. If the variables correlate, the points will fall along a line or curve. The better the correlation, the more points will strongly cluster to the line. It generally gives the idea of the correlation between the variables.
[Figure-4]
In the above figure-4, the positive and Negative correlation is only due to the direction, and in both the correlation, points are clustered to the line but in the last figure in figure-4, Points are not clustered to the line but spread over the X and Y-axis.
Control Chart:-
A line on a control chart is used as a basis for judging the stability of a process. If the observed points are beyond a control limit then it is evidence that special causes are affecting the process.
Control Charts can be used to monitor or evaluate a process.
There are basically two types of control charts, those for variable data and those for attributes data.
Click here to learn more about the Control Chart and Statistical Process Control.
Benefits:-Higher Quality, Lower Unit Cost, Higher effective Capability, etc.
Selection of Control Charts based on Attribute / Variable Type Data:-
Check Sheet is a simple document used for collecting data in real time. Variable or Attribute type data is collected through a Check sheet. A check sheet generally helps to make the decision on the basis of a fact and to collect the data for analysis and evaluation.
Sample check Sheet:-
Logo
Title:-………
Format No-
Issue no-… rev. no-
Date-
Parameters
Specification
Observations
Remarks
Checked by:- Verified by:-
Process Flow diagram/Graphs:-
A process flow diagram is a diagram used to indicate the general flow of plant processes and equipment.
The 7QC tools are the most commonly used tool in the industry for improvement, With the help of the 7QC tools you can understand the process/activities, analyze the data, and interpret the result/graph/output.
Shanti Gopal Pradhan is an experienced professional in Quality Management Systems, QA, Operations, Business Excellence, and Process Improvement. He has strong expertise in international standards including IATF 16949, ISO 9001, ISO 14001, ISO 45001, and ISO 17025, along with methodologies such as TQM, TPM, and Six Sigma.
He holds a degree in Mechanical Engineering along with an MBA, combining strong technical acumen with strategic business insight, he is a Certified Internal Auditor, Lead Auditor, and Six Sigma Black Belt, with a proven track record in driving quality transformation and operational excellence.
How to plot Histogram in Excel with Manufacturing Example
How to plot Histogram in Excel, Step-by-step guidance is described below
A histogram is one of the 7QC tools and commonly used graphs to show frequency distribution. Helps summarize data from a process that has been collected over a period of time.
A histogram is a representation of the frequency distribution of numerical data. it was first familiarized by Karl Pearson. The histogram is related to merely one type of variable data. We have to calculate the interval value to represent the bins. Bins will give you an idea about how much data falls within the selected data range’s width. The histogram gives the indication that data distribution is normal, skewed, or bi-modal.
Advantages of the histogram:
To give an idea about data distribution.
Data distribution can be calculated within a short time duration.
Data that are normal or abnormal can be identified through the graph.
Typical histogram shapes:
1. Symmetric 2. Left skewed 3. Right skewed 4. Bimodal
Bell Shaped/Symmetric:- The data distribution shape of the left side from the average line is similar to the right-side shape, here data is normally distributed within the upper and lower specification limits, such types of data distribution are the safe sign to process operation.
Left/Right Skewed:– Generally in left or right shewed, data are distributed on one side either towards the left or right, which indicates the data are non-normal and there may chance that data can go outside of specification limits if will presence of any special cause in process or any major variation in process characteristics.
Step-by-step guidance to plot the Histogram with an example:-
Here is the full description of How to plot a Histogram in Excel / how to make a histogram in Excel-
In the below temperature reading, we have 100 data but we do not know whether the data are normal or non-normal and also how many data are within the specification limit, after plotting the histogram will give you an indication of data distribution. As you can see the histogram below indicates the data distribution within the bin range.
Step -1
Let’s have 100 numbers temperature readings, so first of all, we need to calculate the count, Max, min, and interval of data as per below-
you can use the Excel formula to calculate the count, Max, and Min. value
(Interval =(max-Min)/9)
Step -2
Now you have to calculate the Bin range of Temp as per the below steps
(445+1.6 I.e (=I5+G7) then enter the “F4” key after “+” & before “G7” of the above formula to freeze the 1.6 interval value in all the columns, then drag )
Step-3
In step -3 you have to calculate the frequency distribution w.r.t temperature bin range, just follow the step 3 explanation in the Excel sheet.
To get the frequency formula in Excel you may follow the below-
( go to the formula then more functions next to statistical then frequency and finally enter frequency)
Step-4
Go to the data section then the data analysis bar and select the histogram
Step-5
After selecting the histogram from the data analysis bar, such a dialogue box will appear, now you have to select the Input range ( select the whole temperature reading ) then select the temperature bin range as described in the arrow as per step -5, and finally enter the ok after selecting the output range( for output range you have to select at any point in excel where you would like to see the graph may be in the same sheet or in new excel sheet)
Now the final histogram will look like this as
If you are not getting the data analysis option in your Excel sheet, then you have to install it in the Excel sheet. we have already written the post on it, if you would like to learn the steps then, read the articles.
as we know the histogram plays a vital role in data analysis and with the help it you can easily understand the frequency distribution and different shapes like Symmetric, Left skewed, Right skewed & Bimodal, etc. and it is frequently used as one of 7 QC tools in manufacturing industries for process improvement.
Histograms are used in many activities like QA analysis, the Six Sigma project, Kaizen, SGA, Quality circle projects, etc.
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Shanti Gopal Pradhan is an experienced professional in Quality Management Systems, QA, Operations, Business Excellence, and Process Improvement. He has strong expertise in international standards including IATF 16949, ISO 9001, ISO 14001, ISO 45001, and ISO 17025, along with methodologies such as TQM, TPM, and Six Sigma.
He holds a degree in Mechanical Engineering along with an MBA, combining strong technical acumen with strategic business insight, he is a Certified Internal Auditor, Lead Auditor, and Six Sigma Black Belt, with a proven track record in driving quality transformation and operational excellence.
