A coin is tossed three times, and $X$ is the number of heads. What is $P(X = 2)$ ?

\frac{1}{8}

Correct answerYour answer

\frac{1}{4}

Correct answerYour answer

\frac{3}{8}

Correct answerYour answer

\frac{2}{3}

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

Of the 8 equally likely outcomes, $HHT$ , $HTH$ and $THH$ have exactly two heads.
$P(X = 2) = \frac{3}{8}$ .

Worth noting

$\frac{1}{4}$ treats the four values 0, 1, 2, 3 as equally likely.

Ten questions from Random Variables, Expectation & Variance, at your own pace.

Ten questions from Random Variables, Expectation & Variance, at your own pace.

A coin is tossed three times, and XXX is the number of heads. What is P(X=2)P(X = 2)P(X=2)?