Elementary Statistics: A Step-by-Step Approach with Formula Card 9th Edition

Published by McGraw-Hill Education
ISBN 10: 0078136334
ISBN 13: 978-0-07813-633-7

Chapter 6 - The Normal Distribution - Review Exercises - Section 6-2 - Page 362: 9


above 130.9 dollars

Work Step by Step

Given $\mu=120. \sigma=10.50$ $15\%$ under the right tail of the distribution corresponds to a z-score of z=1.037 which gives a value $120+1.037\times10.5=130.9$ which means that the cost above 130.9 is considered excessive.
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