Is this equality generally true? | Probability

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The equality P(|Xn - b| ≥ ε) = P(|Xn - b|² ≥ ε²) is generally true for random variables Xn and constants b and c. This equivalence holds because the condition a ≥ b implies a² ≥ b² for any positive numbers a and b. Therefore, the probabilities of these two events are equal, confirming the professor's assertion that they represent the same event.

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Suppose Xn is a random variable. Let b and c be a constant.

Is the following generally true?

P(|X_{n}-b| \geq \epsilon) = P(|X_{n}-b|^{2} \geq \epsilon^{2})

This says that the probability that Xn minus b is greater than or equal to epsilon is equal to the probability that Xn minus b squared is greater than epsilon squared.

My prof keeps saying that they are the same event, therefore, they have the same probability. But I still don't understand. Any insight?

Thanks,
M
 
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Yes, it's generally true. It is because for any positive numbers a and b,

a \geq b

if and only if

a^2 \geq b^2
 

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