Palisades Eco-Park is a small ecological reserve that admits a relatively small number of visitors on any day, but provides both educational and entertaining lectures, exhibitions, and opportunities to observe nature. The company has collected the following data on labor costs and number of visitors to the park over the last 30 months.

Month	Labor Cost		Visitors
1	$	26,420	2,300
2	$	37,134	3,507
3	$	40,897	3,803
4	$	32,383	3,006
5	$	35,618	3,211
6	$	33,432	2,951
7	$	32,767	2,983
8	$	39,225	3,621
9	$	39,464	3,735
10	$	48,023	4,832
11	$	43,137	4,026
12	$	39,937	3,794
13	$	35,244	3,268
14	$	33,944	3,161
15	$	37,831	3,393
16	$	27,116	2,840
17	$	31,376	4,595
18	$	30,657	3,769
19	$	28,232	3,263
20	$	30,700	4,022
21	$	26,289	2,705
22	$	25,228	2,428
23	$	29,563	4,420
24	$	30,854	5,165
25	$	28,773	3,507
26	$	32,426	4,429
27	$	29,317	4,044
28	$	30,622	4,126
29	$	29,099	3,398
30	$	28,522	2,808

Required:

a. Estimate the labor costs assuming 3,100 visitors for the month using the results of a simple regression based on the 30 months of available data. b. What percentage of the variance in the data does the R-squared value explain? c. You learn that starting in month 16, the park started using a different, more automated system for interacting with visitors. Estimate the labor cost assuming 3,100 visitors using the results of a simple regression based on the data for months 16 through 30 only. d. What percentage of the variance in the data does the R-squared value explain?