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Note: We can use the normal distribution as a close approximation to the
 binomial distribution whenever n*p ≥ 5 and nq ≥ 5.
Given a binomial distribution with n = 21 and p = 0.24,
  21·.24 5.04  and 21·.76 = 15.96  
Yes, the normal distribution provide a reasonable approximation to this bionomial distribution