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Probability and Statistics

GATE CSE 2012 · Q21

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Consider a random variable XX that takes values +1+1 and −1-1 with probability 0.5 each. The values of the cumulative distribution function F(x)F(x) at x=−1x = -1 and +1+1 are

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Official answer: C) 0.5 and 1

Probability and Statistics

The cumulative distribution function (CDF) of a random variable XX is defined as:

F(x)=P(X≤x)F(x) = P(X \le x)

Given:

  • P(X=−1)=0.5P(X = -1) = 0.5

  • P(X=+1)=0.5P(X = +1) = 0.5

Calculating the CDF at the given points:

  1. At x=−1x = -1:

F(−1)=P(X≤−1)=P(X=−1)=0.5F(-1) = P(X \le -1) = P(X = -1) = 0.5
  1. At x=+1x = +1:

F(+1)=P(X≤+1)=P(X=−1)+P(X=+1)=0.5+0.5=1.0F(+1) = P(X \le +1) = P(X = -1) + P(X = +1) = 0.5 + 0.5 = 1.0

Thus, the values of F(x)F(x) at x=−1x = -1 and x=+1x = +1 are 0.5 and 1 respectively (Option C).

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This Probability and Statistics previous year question is Q21 of the GATE CSE 2012 paper. Find more GATE CSE PYQs on Probability and Statistics in Engineering Mathematics, or browse all GATE CSE PYQs.

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GateAI solution cardGATE CSE 2012 · Q21 · MCQ

Consider a random variable X that takes values +1 and -1 with probability 0.5 each. The values of the cumulative distribution function F(x) at x = -1 and +1 are

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