A company wishes to check on the efficiency of its call centre. It carries out checks on a sample of 200 customer calls by using computer monitoring equipment which measures the length of calls.

i) the company has one section that rings people who are not existing customers to advise them of a house-painting service. call numbers are selected at random from a list of properties in a specific district. from past experience it is known that the chance of a household in this district wanting painting done is 10%.

so, if a caller rings 12 properties on a particular day, what is the chanced that exactly 2 households want painting done?

ii) what assumptions did you need to make to answer i)? answer in relation to this specific call centre situation.