Representing Bivariate Data in Scatter Plots

Scatter Plots

This is for students that missed class on Monday, March 7. Please complete these slides to catch up on material.​

A scatter plot is a graph that is used to show data between two variables, also known as bivariate data.

• ​For ex: height and weight.​

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Scatter plots show patterns, trends, and associations between variables that could impact each other.​

Scatter Plots

​Positive Association	​Negative Association	​No Association
​Both variables are increasing.	One variable is increasing, the other is decreasing.​	There is no relationship between the variables.​

​Types of Association

Multiple Choice

What type of association does this graph have?

• positive 
• negative
• none
• all of the above

Scatter Plots can be described as linear and non-linear models. They are not perfectly linear or non-linear but they​ follow a trend.

Linear vs. Non-linear Models

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Multiple Choice

Which scatter plot shows a linear relationship between x and y?

• Graph A
• Graph B
• Graph C
• Graph D

​Outliers	​Clusters
​An outlier is a data point in a scatter plot that does not follow the trend of the data.	A group of data points that are closely grouped together.​

​outlier

cluster

Multiple Choice

What are the coordinates of the outlier?

• (1,9)

• (9,1)

• (2,2)

• y=x

To show the overall trend of a data set, we can use a ​Line of Best Fit.

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A line of best fit should:

• Follow the trend of the data

• Split the data in half

• Help to estimate or predict values that are not already given in the set.

Line of Best Fit

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Multiple Choice

Which of the following lines represents the line of best fit for the scatter plot?

• A
• B
• C
• D

Multiple Choice

Which of the following lines represents the line of best fit for the scatter plot?

• A
• B
• C
• D