Question

What is the probability of flipping a coin 8 times and getting heads 2 times? Round your answer to the nearest tenth of a percent.

Answer 1

Step-by-step explanation:

This problem is related to binomial probability

Probability of getting head (success)p= 1/2

Probability of getting tail (failure )q=1/2

Total number of trials(n) = 8

number of success (r)= 3

Binomial probability P(r=3)

$nCr(p)^{n-r}q^r$

Plug in the values in the formula

$nCr(p)^{n-r}q^r\\8C3(\frac{1}{2} )^{8-3}\frac{1}{2} ^3\\ \frac{8!}{3!(8-3)!} (\frac{1}{2} )^8\\56 \cdot (\frac{1}{256} )\\0.21875$

To convert it into percentage , multiply by 100

0.21875 times 100= 21.9

Answer :

21.9%