(a) On average, 2.5 customers per hour return a product for a refund at Goodbuys supermarkets. (i) (b) (ii) Explain why the Poisson distribution would be suitable in this situation for calculating probabilities. (ii) Using the Poisson distribution, calculate the probability of less than 2 customers returning a product in a given hour. Suppose 30% of all Goodbuy's customers use the 'express lanes' at the checkout counter. From a sample taken of 20 customers, 5 used the express lanes. (1) Explain why the Binomial distribution would be suitable in this situation for calculating probabilities. Using the Binomial distribution, calculate the probability of exactly 5 customers from the sample of 20 using the express lanes.