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Fall Velocities for Samara Fruit

Keywords: regression, groups, analysis of covariance


Ryan et al (1994) describe the data as follows:

In autumn, small winged fruit called samara fall off maple trees, spinning as they go. A forest scientist studied the relationship between how fast they fell and their "disk loading" (a quantity based on their size and weight). The samara disk loading is related to the aerodynamics of helicopters.

The data give the loadings and fall velocities for fruit from three trees.

Variable Description

Tree 1 to 3
Loading Disk loading
Velocity Fall velocity


Data File (tab-delimited text)


Ryan, B.F., Joiner, B.L., and Rogosa, D. (1994). Minitab Handbook 3rd edition. Duxbury Press.


Test equality of the regression lines of Velocity on Loading for the three trees.



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