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Scatterplots
One axis represents each variable, data plotted as points
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Response /Dependent variable
measures or records the outcome (y-axis)
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Explanatory /Independent variable
explains changes in the response variable (x-axis)
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Form
linear, non-linear, no relationship, curved, clustered
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Direction
positive, negative, no direction
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Strength
how much scatter around the main form
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Outliers
deviations from the main pattern
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Correlation
- Correlation coefficient (r) - a measure of the direction and strength of a relationship. It is
- calculated using the mean and the standard deviation of both the x and y variables.

- r ranges from -1 to +1
- When variability in one or both variables decreases, the correlation coefficient gets
- stronger (closer to +1 or −1).
- Correlations are calculated using means and standard deviations and thus are NOT
- resistant to outliers.
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