Elementary Statistics (12th Edition)

Published by Pearson
ISBN 10: 0321836960
ISBN 13: 978-0-32183-696-0

Chapter 7 - Estimates and Sample Sizes - Review - Chapter Quick Quiz - Page 373: 6



Work Step by Step

$\alpha=1-0.99=0.10.$ Then, by using the table, the critical value: $z_{\alpha/2}=z_{0.005}=2.58.$ Hence the sample size:$n=\frac{z^2_{\frac{\alpha}{2}}\cdot \sigma^2}{E^2}=\frac{2.58^2\cdot15^2}{2^2}=374.$
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