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Questions › IIT JAM › IIT JAM 2023 › Q42
1 markStatistics › Random variables and standard distributions › Expectation and varianceModerateabout 2 min

IIT JAM 2023 Question 42: Random variables and standard distributions

Let Y∼Normal(3,1)Y\sim\text{Normal}(3,1)Y∼Normal(3,1), W∼Normal(1,2)W\sim\text{Normal}(1,2)W∼Normal(1,2) and X∼Bernoulli(p=0.9)X\sim\text{Bernoulli}(p=0.9)X∼Bernoulli(p=0.9) (X=1X=1X=1 success). Let S=XY+(1−X)WS=XY+(1-X)WS=XY+(1−X)W. Then E(S)=E(S)=E(S)= ________ (round off to 1 decimal place).

Answer and worked solution

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Plain-text version

Let Y~Normal(3,1), W~Normal(1,2) and X~Bernoulli(p=0.9) (X=1 success). Let S=XY+(1-X)W. Then E(S)= (round off to 1 decimal place).

Random variables and standard distributions has come up 173 times in 7 exams since 2005.

What this question tests

This question is on Expectation and variance, part of Random variables and standard distributions in Statistics.

The mean and spread of a random variable, and how they change under transformations and sums.

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Question from the IIT JAM 2023 paper. Solutions are TestStop's own. Not affiliated with or endorsed by any examination authority.