Methods2025 NHT Exam 2 Section A · Q16CAS active1 mark

Standard deviation from symmetric normal probabilities

Let $X$ be a normal random variable that satisfies $\Pr(X > 6) = \Pr(X < 8) = \Pr(Z < 0.5)$ , where $Z \sim \text{N}(0, 1)$ is the standard normal random variable.

The standard deviation of $X$ is

1 mark

A0.5B1C2D4

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