Eighty percent of the employees have their biweekly Wages de

Eighty percent of the employees have their biweekly Wages deposit directly to their bank by electronic deposit program. Suppose we select a random samples of 7 employees.

What is the probability that four of the seven sampled employees use direct deposit program?

Solution

Note that the probability of x successes out of n trials is          
          
P(n, x) = nCx p^x (1 - p)^(n - x)          
          
where          
          
n = number of trials =    7      
p = the probability of a success =    0.8      
x = the number of successes =    4      
          
Thus, the probability is          
          
P (    4   ) =    0.114688 [answer]