Statistics: Informed Decisions Using Data (4th Edition)

Published by Pearson
ISBN 10: 0321757270
ISBN 13: 978-0-32175-727-2

Chapter 8 - Review - Test - Page 422: 3d

Answer

$P(X\gt100)=0.0764$

Work Step by Step

For a random sample of 25 we have: $μ_{X ̅}=μ=90$ $σ_{X ̅}=\frac{σ}{\sqrt n}=\frac{35}{\sqrt {25}}=7$ Let's find the z-score for 100: $z=\frac{X-μ_{X ̅}}{σ_{X ̅}}=\frac{100-90}{7}=1.43$ According to Table V, the area of the standard normal curve to the left of z-score equal to 1.43 is 0.9236. But, we want the area of the standard normal curve to the right of z-score equal to 1.43: $1-0.9236=0.0764$
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