Question

Find the probability that a man flipping a coin gets the fourth tail on the ninth flip.

Answer 1

solution Given that Man flipping a coin gets the 4th tail on the ninth flip. consider that tossing of a coin is a trical Probability of success for each trial P= 1/2 failure for each trial a = 1-4 = / get u let random variable y represent the number of tosses to get y tails : in other words to Success Hence x has a negative binowwal distribution with parameters K=4 P= 1/2 P(x=x) ab(aj kip) ubere nak, ktl ,K+2.. KX-R (n=1) pou

Now lets calculate the probability that person flipping a coin gets the 4th fail on the 9th flip. P(x=9) (9., 4, 1/2) 81614) 8 -()64) 78! () Segyi 5!*3! x 0.0625*0.03125 56x 1.953125 x 10 5x 103 2 0.109375 Finally P(x29) 50.109375