5-7: Scatter Plots5-7: Scatter Plots

& Lines of Best Fit & Lines of Best Fit

What is a scatter plot?What is a scatter plot?

A graph in which two sets of data are plotted as ordered pairs

When looking at the graph you can see the relationship between the two variables.

A graph in which two sets of data are plotted as ordered pairs

When looking at the graph you can see the relationship between the two variables.

When we look at relationships of x and y…

When we look at relationships of x and y…

There are 3 possibilitiesPositive Correlation Negative CorrelationNo Correlation

There are 3 possibilitiesPositive Correlation Negative CorrelationNo Correlation

Positive Correlation Positive Correlation

As x increases, y increases Has a positive slope.

As x increases, y increases Has a positive slope.

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Negative Correlation Negative Correlation

As x increases, y decreases Has a negative slope.

As x increases, y decreases Has a negative slope.

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NO Correlation NO Correlation

No relationship between x and y. No relationship between x and y.

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Lines of Best FitLines of Best Fit

A line which describes the trend of the data.

You will determine the line of best fit, by sketching a line which passes through as many points as possible.

A line which describes the trend of the data.

You will determine the line of best fit, by sketching a line which passes through as many points as possible.

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Finding Equations of Lines of Best Fit

Finding Equations of Lines of Best Fit

1) Plot the data

2) Sketch a line of best fit, passing through as many points as possible.

3) Choose 2 points on your line and find the equation of the line.

a) find the slope

b) Write the equation of the line in slope intercept form. (y = mx + b)

1) Plot the data

2) Sketch a line of best fit, passing through as many points as possible.

3) Choose 2 points on your line and find the equation of the line.

a) find the slope

b) Write the equation of the line in slope intercept form. (y = mx + b)

Let’s Do It!Let’s Do It!

Close your laptop and plot the data on

the notesheet.

Close your laptop and plot the data on

the notesheet.