We represent the years as 1 to 50 on x and the Co2 concentration
data as y
The data can be represented exponentially as y =
a.bx
Year
|
x
|
y
|
Y = log y
|
x*Y
|
X^2
|
1961
|
1
|
41.58
|
1.6189
|
1.6189
|
1
|
1962
|
2
|
42.01
|
1.6234
|
3.2467
|
4
|
1963
|
3
|
43.25
|
1.6360
|
4.9080
|
9
|
1964
|
4
|
43.24
|
1.6359
|
6.5435
|
16
|
1965
|
5
|
43.16
|
1.6351
|
8.1754
|
25
|
1966
|
6
|
45.01
|
1.6533
|
9.9199
|
36
|
1967
|
7
|
46
|
1.6628
|
11.6393
|
49
|
1968
|
8
|
46.57
|
1.6681
|
13.3448
|
64
|
1969
|
9
|
48.34
|
1.6843
|
15.1588
|
81
|
1970
|
10
|
49.07
|
1.6908
|
16.9082
|
100
|
1971
|
11
|
49.92
|
1.6983
|
18.6810
|
121
|
1972
|
12
|
51.07
|
1.7082
|
20.4980
|
144
|
1973
|
13
|
53.48
|
1.7282
|
22.4665
|
169
|
1974
|
14
|
54.09
|
1.7331
|
24.2636
|
196
|
1975
|
15
|
54.97
|
1.7401
|
26.1019
|
225
|
1976
|
16
|
55.87
|
1.7472
|
27.9549
|
256
|
1977
|
17
|
57.75
|
1.7616
|
29.9464
|
289
|
1978
|
18
|
59.01
|
1.7709
|
31.8767
|
324
|
1979
|
19
|
60.47
|
1.7815
|
33.8493
|
361
|
1980
|
20
|
62.46
|
1.7956
|
35.9120
|
400
|
1981
|
21
|
63.91
|
1.8056
|
37.9169
|
441
|
1982
|
22
|
65.14
|
1.8138
|
39.9047
|
484
|
1983
|
23
|
66.75
|
1.8245
|
41.9624
|
529
|
1984
|
24
|
68.43
|
1.8352
|
44.0459
|
576
|
1985
|
25
|
69.93
|
1.8447
|
46.1166
|
625
|
1986
|
26
|
71.21
|
1.8525
|
48.1661
|
676
|
1987
|
27
|
72.84
|
1.8624
|
50.2840
|
729
|
1988
|
28
|
75.22
|
1.8763
|
52.5373
|
784
|
1989
|
29
|
76.67
|
1.8846
|
54.6541
|
841
|
1990
|
30
|
78.16
|
1.8930
|
56.7895
|
900
|
1991
|
31
|
80.34
|
1.9049
|
59.0529
|
961
|
1992
|
32
|
80.66
|
1.9067
|
61.0131
|
1024
|
1993
|
33
|
81.28
|
1.9100
|
63.0295
|
1089
|
1994
|
34
|
82.68
|
1.9174
|
65.1916
|
1156
|
1995
|
35
|
84.79
|
1.9283
|
67.4921
|
1225
|
1996
|
36
|
86.41
|
1.9366
|
69.7163
|
1296
|
1997
|
37
|
87.8
|
1.9435
|
71.9093
|
1369
|
1998
|
38
|
90.3
|
1.9557
|
74.3161
|
1444
|
1999
|
39
|
92
|
1.9638
|
76.5877
|
1521
|
2000
|
40
|
92.82
|
1.9676
|
78.7057
|
1600
|
2001
|
41
|
95.02
|
1.9778
|
81.0904
|
1681
|
2002
|
42
|
96.55
|
1.9848
|
83.3596
|
1764
|
2003
|
43
|
99.35
|
1.9972
|
85.8782
|
1849
|
2004
|
44
|
101.61
|
2.0069
|
88.3052
|
1936
|
2005
|
45
|
103.24
|
2.0138
|
90.6232
|
2025
|
2006
|
46
|
105.94
|
2.0251
|
93.1528
|
2116
|
2007
|
47
|
107.43
|
2.0311
|
95.4629
|
2209
|
2008
|
48
|
109.49
|
2.0394
|
97.8900
|
2304
|
2009
|
49
|
111.18
|
2.0460
|
100.2553
|
2401
|
2010
|
50
|
114.22
|
2.0577
|
102.8871
|
2500
|
Sum
|
1275.000
|
|
91.980
|
2441.310
|
42925.000
|
?Y = AN+B?X
91.98 = 50A + 1275B     ……(I)
?XY = A?X + B ?X2
2441.31 =1275A + 42925BÂ Â
         Â
…(II)
SOLVING (I) AND (II) WE GET,
A
=1.602Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
B =0.0092
Now , a = Antilog(1.602) = 39.99,
            Â
b = Antilog(0.0092) = 1.021
The exponential regression is thus given as,
Y =40(1.021)x
To estimate Co2 levels in 2015, we put x = 55
Y =40(1.021)55 = 125.4 ppm