Scatter diagram is the graphical presentation of relationship between two variables. Scatter diagram is an important tool out of 7 fundamental tools of quality control. Scatter diagram helps to confirm the degree of relationship between cause and effect. Here cause is an independent variable and effect is dependent variable. Scatter diagram is an important statistical tool to analyze the relationship of two variables. To create the scatter diagram take the values of independent variable on X-Axis where as the dependent variable is taken on Y-Axis. Plot the intersection points of X and Y on the graph. Draw a straight line passing through all the points. Analyze the pattern of the points. For different degree of relationship different pattern of scatter diagram is formed. If Y increases as X increases and data points are on the straight line then there is perfect positive correlation. If Y decreases with increase of X and data points are on the straight line then there is perfect negative correlation. But when data is scattered all over the graph then there is zero correlation.

1. SEVEN QC TOOLS TRAINING
Scatter Diagram

2. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Introduction Scatter diagram is the graphical presentation of cause and effect relationship. Hence it is also called correlation graph of cause and effect. Cause is an independent variable taken on X-Axis while the effect is dependent variable and taken on Y- Axis. Scatter diagram helps in analysis of degree of impact of cause on the effect.

3. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Scatter diagram study the changes in behavior of effect when change in cause takes place. The data of independent and dependent variables are scattered across the straight line on a graph paper. Scatter diagram shows that how dependent variable behaves when independent variable increases or decreases?

4. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Different Patterns of Scatter Diagram
Perfect Positive Correlation Graph
When indpendent variable increases dependent varible also increases, all data points are on staright line.
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5. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Perfect Negative Correlation Graph
When independent variable increases dependent variable decreases, all data points are on a straight line.
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6. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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High Degree of Positive Correlation
Dependent variable increases with independent varible but all data points scatter around the straight line.
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7. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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High Degree of Negative Correlation
Dependent variable decreases with increase in independent variable and all data points scatter around the straight line.
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8. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Zero Correlation
Data points scattered all over the graph, No pattern of data points, There is no correlation.
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9. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Algebraic Value Of Correlation
The value of degree of correlation between two variable X and Y is given as ̅ ̅ √ ̅ ̅

10. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Interpretation of ‘r’

11. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Example Problem
X=10, 20, 30, 40, 50, 60
Y=25, 50, 75, 100, 125, 150
Construct the scatter diagram and analyse the degree of correlation between X and Y.

12. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Solution
The scatter diagram formed shows that X and Y has perfect positive correlation.
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Scatter Diagram

13. SEVEN QC TOOLS TRAINING: SCATTER DIAGRAM
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Contact
Narender Sharma
Mob: 08684861131, 09315132462
Website: www.shakehandwithlife.in | www.shakehandwithlife.puzl.com | www.shakehandwithlife.blogspot.in
Email: shakehandwithlife@gmail.com | narender@shakehandwithlife.in