A large school is sending 6 children to camp If 20 of the ch

A large school is sending 6 children to camp. If 20% of the children in the school are first graders, and the 6 children are selected at random from among all 6 grades at the school, what is the probability that at most one first grader is chosen?

Solution

Using a cumulative binomial distribution table or technology, matching          
          
n = number of trials =    6      
p = the probability of a success =    0.2      
x = the maximum number of successes =    1      
          
Then the cumulative probability is          
          
P(at most   1   ) =    0.65536 [answer]