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	$	26,120	2,000
2	$	36,712	3,050
3	$	40,432	3,307
4	$	32,015	2,614
5	$	35,213	2,792
6	$	33,052	2,566
7	$	32,395	2,594
8	$	38,780	3,149
9	$	39,016	3,248
10	$	47,478	4,202
11	$	42,647	3,501
12	$	39,483	3,299
13	$	34,844	2,842
14	$	33,559	2,749
15	$	37,401	2,950
16	$	26,808	2,469
17	$	31,020	3,996
18	$	30,309	3,277
19	$	27,911	2,838
20	$	30,351	3,497
21	$	25,991	2,352
22	$	24,942	2,111
23	$	29,227	3,844
24	$	30,503	4,491
25	$	28,446	3,050
26	$	32,058	3,851
27	$	28,984	3,517
28	$	30,274	3,588
29	$	28,769	2,954
30	$	28,198	2,442

Required:

a. Estimate the labor costs assuming 2,800 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 2,800 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?