A fair coin is tossed 5 times. What is the probability of at least 4 heads?

\frac{1}{32}

Correct answerYour answer

\frac{3}{32}

Correct answerYour answer

\frac{5}{32}

Correct answerYour answer

\frac{3}{16}

Correct answerYour answer

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CorrectNot quiteAnswer D

Correct answer: D

At least 4 means 4 or 5: ${}^{5}C_{4} + {}^{5}C_{5} = 5 + 1 = 6$ of the $2^{5} = 32$ outcomes.
$P = \frac{6}{32} = \frac{3}{16}$ .

Worth noting

$\frac{5}{32}$ is exactly 4 heads; 'at least 4' takes in all 5 as well.

Ten questions from Binomial & Poisson Distributions, at your own pace.

Ten questions from Binomial & Poisson Distributions, at your own pace.

Explanation