GATE 2015 EE (EE2) – Question 37

Engineering Mathematics · Probability and Statistics: Conditional probability · 2 marks · Multiple choice

Coins R,S have joint probabilities HH,TT,HT,TH equal to 0.28,0.18,0.30,0.24 respectively. Which is true?

Show answer and explanation

Correct answer: (D) The tosses are dependent.

Explanation

The head probability for R is 0.28+0.30=0.58. For S it is 0.28+0.24=0.52, so neither coin is fair.

Independence would require P(HH)=P(HR)P(HS)=0.58×0.52=0.3016, which differs from the stated 0.28. Therefore the tosses are **dependent, D**.

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