+0  
 
0
469
1
avatar

If you flip a fair coin 7 times, what is the probability that you will get exactly 2 tails?

 Jan 13, 2019
 #1
avatar+128079 
+2

This is a binomial probability

 

P(2 tails)  = C(7,2) * (1/2)^2 * (1/2)^5  =  C(7, 2) (1/2)^7  =  21 / 128

 

 

cool cool cool

 Jan 13, 2019
edited by CPhill  Jan 13, 2019

4 Online Users