What is the probability of obtaining exactly 4 HEADS? Give your answer as a decimal number, with 4 decimal places.

Question

An unfair coin with 0.66 probability of TAILS is flipped 6 times. What is the probability of obtaining exactly 4 HEADS? Give your answer as a decimal number, with 4 decimal places.

Answer 1

Use the formula

P(4)=6C4xp^4q^2

were p is probability of favorable event, in our case it is 1-0.66=0.34

q is probability of unfavorable event, in our case it is 0.66

6C4=6!/(4!(6-4)!)=15

P(4)=15x0.34^4x0.66^2=0.0873