Elementary Statistics (12th Edition)

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

Chapter 3 - Statistics for Describing, Exploring, and Comparing Data - 3-3 Measures of Variation - Basic Skills and Concepts - Page 110: 33


Not unusual.

Work Step by Step

If a value is unusual, then it is more than two standard deviations far from the mean. $Minimum \ usual \ value=mean-2\cdot(standard \ deviation)=77.5-2\cdot11.6=54.3$ $Maximum \ usual \ value=mean+2\cdot(standard \ deviation)=77.5+2\cdot11.6=100.7$. Here, $54.3<99<100.7$, therefore the value is not unusual, because it is between the minimum and maximum usual value mean.
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