Watch help video
If a fair coin is tossed 5 times, what is the probability, to the nearest thousandth, of getting exactly 3 tails?

Answer

Expert–verified

Hide Steps

Answer

Calculate probability: $P (X = 3) = 10 \times 0.125 \times 0.25 = 0.3125$

Steps

Step 1 ：Use the binomial probability formula: $P (X = k) = (\binom{n}{k}) p^{k} (1 - p)^{n - k}$

Step 2 ：Substitute values: $P (X = 3) = (\binom{5}{3}) {0.5}^{3} (1 - 0.5)^{5 - 3}$

Step 3 ：Calculate probability: $P (X = 3) = 10 \times 0.125 \times 0.25 = 0.3125$