Education Technology

Influential Outliers Application

Published on 08/30/2010

Activity Overview

Students identify outliers that are influential in respect to the variation of the data values and describing the role of the location of a point relative to the other data in determining whether that point has influence on the coefficient of determination.

Key Steps

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    Students are shown a scatter plot of data with the regression line graphed. They will grab and drag a point, forcing it to become an outlier. As they do so, they will observe how the explained and unexplained deviations, represented by the solid lines and the dotted lines, change.

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    Students are introduced to the coefficient of determination and what it tells them about the amount of total variation that can be explained by the linear relationship. They will observe the coefficient of determination, the r² value, as they move a point around the other data values. They will focus on when the point is an outlier and the effect it has on the r² value.