Exercise · ZW-CHEBYSHEV-INEQUALITY-006 · ★★☆ Intermediate

If \(X\) has mean 100 and standard deviation 10, what minimum probability does Chebyshev guarantee for \(70<X<130\)?

Choose one option.

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  • C. \(\tfrac89\)

Explanation

The interval is \(\mu\pm3\sigma\); the probability is at least \(1-\tfrac19=\tfrac89\).

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Review the concept: Chebyshev inequality

Chebyshev's inequality bounds the probability \(P\) that a variable \(X\) deviates from its mean \(\mu\) by more than \(k\) standard deviations \(\sigma\), using only its variance.

\[P\big(|X-\mu|\ge k\sigma\big)\le\dfrac{1}{k^2}\]

More practice problems: chebyshev inequality

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