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1 year ago

Suppose that X is a random variable with mean and variance both equal to 20. What can be said about P{0 ≤ X ≤ 40}.

Mathematics

1 answer:

Dennis_Churaev [7]1 year ago

5 0

Answer:

$P(0 \leq X \40) = \frac{19}{20}$

Step-by-step explanation:

We know that:

$P(|X - 20| < 20) + P(|X - 20| \geq 20) = 1$

$P(0 \leq X \leq 40) = P(0-20 \leq X-20 \leq 40-20) = P(-20 \leq X \leq 20) = P(|X - 20| \leq 20)$

$P(|X - 20| \leq 20) = 1 - P(|X - 20| > 20) = 1 - \frac{20}{20^{2}} = \frac{19}{20}$

$P(0 \leq X \40) = \frac{19}{20}$

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0.0413 is the probability that less than 4 out of 10 U.S. adults have very little confidence in newspapers.

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