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A Wrong Approach
We cannot divide the sample into groups according
to lifetime habits
•Suppose
we consider
–Ever
hang glided (hung glide?) vs Constant coward
•We
might detect spurious associations due to “survivorship”
–If we started study at birth, we might find hang gliding is
beneficial
•Most
people don’t start hang gliding until teenaged
•We would detect the fact that hang gliders survived at
least that long