Bus and subway ridership in Washington, DC, during the summer months is believed to be heavily tied to the number of tourists visiting the city. During the past twelve years, the following data have been obtained. Year Tourist Ridership
1 7 15
2 2 10
3 6 13
4 4 15
5 14 25
6 15 27
7 16 24
8 12 20
9 14 27
10 20 44
11 15 34
12 7 17
(a) Plot the data and determine if a linear model is reasonable.
(b) develop a regression model.
(c) What is the expected ridership if 10m people visit the city?
(d) If there are no tourists at all, explain the predicted ridership?
(e) Use excel to develop a regression model for the data. Explain what excel output indicates about the usefulness of this model.