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If about 68 percent of values lie within one standard deviation, the share lying outside three deviations is roughly:
A68 percent
B0.3 percent
C5 percent
D32 percent
Answer & Solution
Correct answer: B. 0.3 percent
1. The empirical rule states how much lies inside each band.
2. About 99.7 percent of the x values lie within three standard deviations of the mean.
3. Everything else lies outside, which is 100 minus 99.7.
4. That leaves roughly 0.3 percent, or about three values in a thousand.
5. 5 percent is the share outside two deviations, and 32 percent the share outside one.
_Source: OpenStax Introductory Statistics 2e (CC BY 4.0), Ch 6 'The Normal Distribution', sections 6.1-6.3_
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