# 28. Shoreline Park in Mountain View, California, has kept close tabs on the number of patrons…

28. Shoreline Park in Mountain View, California, has kept close tabs on the number of patrons using the park since its opening in January 1993. For the first six months of 2013, the following figures were recorded Month Number of Patrons Month Number of Patrons January February March 133 183 285 April May June 640 1,876 2,550 i. Draw a graph of these six data points. Assume that January- period 1, February- period 2, and so on. Using a ruler, “eyeball” the best straight-line fit of the data. Estimate the slope and intercept from your graph 2.8 Trend-Based Methods 79 b. Compute the exact values of the intercept a and the slope b from the regression equations. c. What are the forecasts obtained for July through December 2013 from the regression equation determined in part (b)? 30. For the data in Problem 28, use the results of the regression equation to estimate the slope and intercept of the series at the end of June. Use these numbers as the initial values of slope and intercept required in Holt’s method. Assume that α , 15, β-.10 for all calculations. a. Suppose that the actual number of visitors using the park in July was 2,150 and the number in August was 2,660. Use Holt’s method to update the estimates of the slope and intercept based on these observations. gives for the number of park visitors in September and October? December? b. What are the one-step-ahead and two-step-ahead forecasts that Holt’s method c. What is the forecast made at the end of July for the number of park attendees in