SOLUTION: A fair coin is thrown repeatedly. What is the probability that on the n th throw A) a head appears for the first time B) the number of tails and heads to date are equal C) exac

Algebra ->  Probability-and-statistics -> SOLUTION: A fair coin is thrown repeatedly. What is the probability that on the n th throw A) a head appears for the first time B) the number of tails and heads to date are equal C) exac      Log On


   



Question 779221: A fair coin is thrown repeatedly. What is the probability that on the n th throw
A) a head appears for the first time
B) the number of tails and heads to date are equal
C) exactly two heads have appeared altogether to date
D) at least two heads have appeared to date

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A fair coin is thrown repeatedly. What is the probability that on the n th throw
A) a head appears for the first time:: (1/2)^n
-----------------------
B) the number of tails and heads to date are equal::: (n/2)(1/2)^n
----------------------------------
C) exactly two heads have appeared altogether to date:: nC2(1/2)^n
-------------------------
D) at least two heads have appeared to date:: 1- nC(n-2)[(1/2)^n]
==================
Cheers,
Stan H.