a) What are the main differences between Time Series method and OLS method? How can you explain randomness in Time Series? (8 points). b) You were hired by a company which wants to understand the demand for hotel rooms in London. This company provides you monthly data with the number of guests in this hotel, the number of all visitors in London, whether the guest is a foreigner, whether the guest arrived by Air, the average number of nights of hotel's guests, and average expenditure of hotel's guest. If the company wants you to provide a forecast for the following months, what would be your econometric model? (7 points) c) If the data starts in 2002 and ends in 2020, how would you deal with the Olympics 2012 and the Pandemic? (5 points) d) If you want to measure the increase in the demand for hotel rooms during the Wimbledon tennis tournament (annual event in July), what do you have to do? (5 points)