# Scatter Diagram | What is Scatter Diagram in 7 QC Tools? | Correlation Chart

## What is a Scatter Diagram in 7 QC Tools:

→**Scatter Diagram**is used to study and identify the possible relationship between two variables.

→ It is used to establish the existence of a correlation, Type of correlation, and Strength of the relation.

→ Scatter Diagram is the best validation tool of Basic Seven QC Tools.

→ It is a graph in which the values of two variables are plotted along two axes of the graph, the pattern of the resulting points will say the correlation between two variable.

→ It is also called a correlation chart.

### ➤ Examples of the relation between the two variables:

→ Weight and Height of a man.

→ Hardness and carbon content in the product.

→ Visual Inspection mistakes and Illumination levels.

→ Child’s height and Father’s height.

→ Curing Temperature and Curing Time

→ Advertising and sales

→ Hardness and carbon content in the product.

→ Visual Inspection mistakes and Illumination levels.

→ Child’s height and Father’s height.

→ Curing Temperature and Curing Time

→ Advertising and sales

## Four Easy Steps for Making a Scatter Diagram:

- Collect data for we have to find a correlation.
- Choose an independent and dependent variable.
- Construct the Graph and add the titles & trend line.
- Interpret the Graph

### ➤ Step 1. Collect data for we have to find a correlation between two variable:

→ Here we took 50 reading of curing temperature and curing time for a product

→ We have to find is any correlation is present or not between curing temperature and curing time.

→ If we have more data sample then it will give a more precise result.

### ➤ Step 2. Choose Independent and Dependent Variable:

→ The dependent variable is usually plotted along the vertical axis i.e. in Y-axis.

→ And dependent variable also called as a measured parameter.

→ The independent variable and is usually plotted along the horizontal axis i.e. in X-axis.

→ The independent variable also called as a control parameter.

→ The independent variable also called as a control parameter.

### ➤ Step 4. Interpret the Scatter Diagram in 7 QC Tools:

**Scatter Diagram**then we will found seven different types of

correlation between the two variable.

### ➤ The seven different correlation between variable

- Strong Positive correlation
- Moderate Positive correlation
- Weak Positive correlation
- Strong Negative correlation
- Moderate Negative correlation
- Weak Negative correlation
- Random Pattern (No correlation)

→ [7] Random Pattern (No correlation) between two variable:

## Benefits of a Scatter Diagram:

→ It is beneficial to confirm a hypothesis (assumption) between two variables that these are related or not.→ Provide both visual and statistical means to test the strength of a potential relationship.

→ It is a very good validation tool.

→ Used for proving the relation between cause and effect.

→ Plotting the diagram is relatively simple.

## Limitation of the Scatter Diagram:

→

**Scatter Diagram**are unable to give you the exact extent of correlation.
→ It does not show you the quantitative measure of the relationship between the variable.

→ This chart does not show you the relationship for more than two variables at a time.

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