Suppose that you flip a coin 15 times. What is the probability that you achieve at least 6 tails?

Answer 1

n = 15 trials

p = 0.5 (success probability)

x = 6 trials with tails

X ~ Binomial (15, 0.5)

Use the binomial probability formula to determine what are your chances of flipping at least 6 coins with tails.

P(X = x) = C(15, x) * (0.5)^x * (0.5)^n-x

P(X ≥ 6) = 1 - P(X < 6) = 1 - 0.1509 = 0.8491

The probability that you achieve at least 6 tails is about 0.8491.