Ralph Billett is the manager of a real estate agency. He now wishes to develop a forecast of the number of houses that will be sold by the agency over the next year. The agency's quarter-by-quarter sales figures over the last three years are shown below.

(a) Determine the seasonal factors for the four quarters.

(b) After considering seasonal effects, use the last-value method to forecast sales in Quarter 1 of next year.

(c) Assuming that each of the quarterly forecasts is correct, what would the last-value method forecast as the sales in each of the four quarters next year?

(d) Based on his assessment of the current state of the housing market, Ralph's best judgment is that the agency will sell 100 houses next year. Given this forecast for the year, what is the quarter-by-quarter forecast according to the seasonal factors?