The Basic Practice of Statistics 7th Edition

Published by W. H. Freeman
ISBN 10: 1-46414-253-X
ISBN 13: 978-1-46414-253-6

Chapter 0 - Getting Started - Chapter 0 Exercises: 0.1a

Answer

The lurking variables that affected the trials include the supplement takers' willingness to live a healthy lifestyle (as exhibited by their taking of possibly preventative supplements) and the "healthy user" bias that results.

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