The Basic Practice of Statistics 7th Edition

Published by W. H. Freeman
ISBN 10: 146414253X
ISBN 13: 978-1-46414-253-6

Chapter 18 - Inference in Practice - Apply Your Knowledge - Page 420: 18.6b

Answer

$\approx0.735$

Work Step by Step

$z=1.96$ Thus the margin of error: $z\frac{\sigma}{\sqrt n}=1.96\frac{7.5}{\sqrt{400}}\approx0.735$
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