The following data is on
X=Automobile Stock per capita,
P= Relative price of automobiles and
Id= Real disposable income per capita
Years
Xt
Pt
Idt
Years
Xt
Pt
Idt
1921
4.8
120.9
407.8
1937
8.34
100
551.2
1922
5.42
111.2
460.4
1938
7.78
109.3
511
1923
6.88
100.6
509.2
1939
7.72
104.9
547.9
1924
7.84
90.9
509.3
1940
8.22
97.1
578.8
1925
8.41
81.7
525.6
1941
9.17
120.1
642.7
1926
8.93
92.6
532.3
1942
7.42
119
719.1
1927
8.77
105.6
543.3
1943
5.79
204.7
741.6
1928
9.13
91
545.1
1944
4.45
356.7
798
1929
9.69
95.1
576.2
1945
3.51
449.3
787.2
1930
9.09
85.9
525.2
1946
4.05
338.6
743.2
1931
8.1
102.4
498.2
1947
5.29
263.4
696.4
1932
6.91
107.9
417.4
1948
6.1
236.2
721.2
1933
6.34
95.6
394.3
1949
8.07
159.7
696.7
1934
6.17
107
421.4
1950
10.25
161.8
745.8
1935
6.53
105.2
475.2
1951
11.46
161.2
743.9
1936
7.51
109.3
525.6
1952
11.19
169.4
753.7
a) Divide the data into four equal parts and obtain the regression
Xt=α + β Pt + γ Idt + εt
for each part. Apply Bartlett’s test to check the heteroscedasticity.
b) Repeat part (a) for the regression
ln Xt=α + β ln Pt + γ ln Idt + εt
and again apply Bartlett test and draw conclusion