DevelopMaths.com High School Maths

Scatter Diagrams

Scatter diagrams show the link between two variables. The variables are plotted as coordinates. This link shows the correlation (relationship) between the two variables.

There are 3 types of correlation

1.	Positive correlation
	As the value of the first variable increases so does the second

2.	Negative correlation
	As the value of the first variable increases the second decreases

3.	No correlation
	No linear relationship between the variables

Example 1. Plot a scatter diagram of this table, what type of correlation is there?

Height m	1	2	3	4	5	6
Weight kg	4	5	6	7	9	9

There is a Postive Correlation

Example 2. Plot a scatter diagram of this table, what type of correlation is there?

Age in Years	1	2	3	4	5
Value of Car £000s	19	16	15	14	12

There is a Negative Correlation

Example 3. Plot a scatter diagram of the two tests, what type of correlation is there?

Art	6	9	1	2	6	2	10
Maths	5	19	10	7	12	18	12

There is No Correlation

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