State two conditions which must be satisfied for a situation to be modelled by a binomial distribution.
In a certain village 28\% of all cars are made by Ford.
14 cars are chosen randomly in this village. Find the probability that fewer than 4 of these cars are made by Ford.
A random sample of 50 cars in the village is taken. Estimate, using a normal approximation, the probability that more than 18 cars are made by Ford.