The GATE Grind

GATE 2017 CS – Question 29

Engineering Mathematics · Probability and Statistics · 1 mark · Numerical answer

Let $X$ be a Gaussian random variable with mean 0 and variance $\sigma^2$. Let $Y = \max(X, 0)$ where $\max(a, b)$ is the maximum of $a$ and $b$. The median of $Y$ is ________.

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Correct answer: 0

Explanation

The variable $X$ is symmetric about 0, so $P(X \leq 0) = 0.5$. Whenever $X \leq 0$, $Y = 0$, so $P(Y = 0) = 0.5$. The median is the value where the cumulative probability first reaches 0.5, which is 0.