Question 4 4 a) A sample of employees of an IT company has been surveyed. Data has been collected on salary, years in education, years of experience, age and gender. Explain how a researcher can include the categorical data on gender in a multi-regression analysis. You should state the number of variables required. b) A company is considering an advertising campaign to increase sales. Without an advertising campaign, the annual revenue () is expected to be 210 000 If the company carries out a local advertising campaign, there is a 30% chance that the annual revenue will be 150 000, a 60% chance that the annual revenue will be 200 000 and a 10% chance that the annual revenue will be 500 000 If the company carry out a national advertising campaign, there is a 10% chance that the revenue will be 150 000, a 65% chance that the revenue will be 300 000 and a 25% chance that the revenue will be 550 000. A local advertising campaign costs 20 000. A national advertising campaign will cost 125 000 i) Construct a decision tree which represents this management decision. Advise the company as to which, if any advertising campaign, they should carry out ii) Due to changes in the economy, the cost of a national advertising campaign has risen to 150 000. Advise the company as to what course of action they should take. Briefly justify your