It is note that 8% of Kaplan students are left handed. If 20 (TWENTY) students are randomly selected, calculate the

Prob of none left handed:   0.92^20

 

Prob exactly 1 left handed:   0.08*(0.92^19)*20    (20 because there are 20 ways of choosing the 1)

 

Prob exactly 2 left handed:  (0.08^2)*(0.92^18)*190.  (190 because there are ncr(20,2) = 190 ways of choosing a pair)

 

Sum the three probabilities above to get the probability of "at most" 2.