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NZAMT NZQA NZ Grapher NZ Maths Census at School Study It


1.11 Bivariate Home | Assessment Criteria | Ask a Question | Make a Plan | Collecting Data | Cleaning Data | Making Scatterplots | Describing Scatterplots | Outliers | Line of Best Fit | Population Inference | Conclusion | Revision


Outliers and Groupings

Identify and discuss outliers.

Identify and discuss any groupings seen

Measures of Central Tendency
Class notes, Blank notes




What do I look for in scatter plots? Anything unusual

Do you see any outliers?  

unusually far from the trend

Do you see any groupings?


What do I see in these scatter plots?

An Outlier is a data point significantly far from the trend or group of other data.

Is the outlier an error? So remove it

Is the outlier an actual data value? Then produce TWO regression models
                  1) With outlier
                  2) Without outlier: is there significant variation

Is it appropriate to remove outlier?

Do NOT remove outlier just to make model (line) fit better!

Discuss what the outlier could be and if it is appropriate to remove or not.



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