What is the probability of flipping a coin four times and getting at least one head?

Instruction: Calculate the probability of at least one head in four independent fair coin tosses using the complement event.

Context: This question assesses the candidate's ability to work with complement probabilities to solve a problem.

Updated

Official answer

Assume four independent fair tosses. The complement of at least one head is all tails, with probability (1/2)^4 = 1/16.

Thus P(at least one head) = 1−1/16 = 15/16 = 93.75%. This includes one, two, three or four heads. Exactly one head would instead have probability C(4,1)/16 = 1/4.

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