Exercise · ZW-PROBABILITY-MASS-FUNCTION-006 · ★★☆ Intermediate
Three fair coins are tossed and \(X\) is the number of heads. Compute \(p_X(2)\).
Choose one option.
Show answer
- D. 3/8
Explanation
The outcomes with two heads are HHT, HTH and THH: 3 out of 8, that is \(\tfrac38\).
Review the concept: Probability mass function
The probability mass function \(p_X\) of a discrete random variable \(X\) gives, for each value \(x\) it can take, the probability \(P\) that it takes it.
\[p_X(x)=P(X=x)\]
More practice problems: probability mass function
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- ZW-PROBABILITY-MASS-FUNCTION-007 Which statement about a probability mass function is correct?
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- ZW-PROBABILITY-MASS-FUNCTION-009 Let p(x)=(tfrac12)^x for x=1,2,3,dots. Compute the probability that X is even.
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