Answer
.1357
Not statistically significant
Work Step by Step
The z value is the sample mean is decreased by mean and divided by the deviation.
z = $\frac{x-u}{o/\sqrt n}$ = $\frac{48.9-50}{15/\sqrt 225}$ = -1.1
Using a z table:
.1357
The Basic Practice of Statistics 7th Edition
by Moore, David S.; Notz, William I.; Fligner, Michael A.
Published by
W. H. Freeman
ISBN 10:
146414253X
ISBN 13:
978-1-46414-253-6
Chapter 17 - Tests of Significance: The Basics - Apply Your Knowledge - Page 400: 17.11a
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