Population regression function - A hypothetical example for CHapter 6, Gujarati

Hypothetical country with population of 60 families. Study the relationship between weekly family consumption expenditure Y and weekly after-tax or disposable family income X. Predict the (population) mean level of weekly consumption expenditure knowing the family's weekly income.

Divide the 60 families into 10 groups of approximately the same income & examine the consumption in each of these groups:

X	80	100	120	140	160	180	200	220	240	260	Mean
Y Weekly Family Consumption Expenditure Y ($)
	55	65	79	80	102	110	120	135	137	150	103.3
	60	70	84	93	107	115	136	137	145	152	109.9
	65	74	90	95	110	120	140	140	155	175	116.4
	70	80	94	103	116	130	144	152	165	178	123.2
	75	85	98	108	118	135	145	157	175	180	127.6
		88		113	125	140		160	189	185	100
				115				162		191
Total	325	462	445	707	678	750	685	1043	966	1211	727.2

X	80	100	120	140	160	180	200	220	240	260
	1/5	1/6	1/5	1/7	1/6	1/6	1/5	1/7	1/6	1/7
	1/5	1/6	1/5	1/7	1/6	1/6	1/5	1/7	1/6	1/7
	1/5	1/6	1/5	1/7	1/6	1/6	1/5	1/7	1/6	1/7
	1/5	1/6	1/5	1/7	1/6	1/6	1/5	1/7	1/6	1/7
	1/5	1/6	1/5	1/7	1/6	1/6	1/5	1/7	1/6	1/7
		1/6		1/7	1/6	1/6		1/7	1/6	1/7
				1/7				1/7		1/7
means of Y	65	77	89	101	113	125	137	149	161	173

	Sample 1	Sample 2
X	Y1	Y2
80	70	55
100	65	88
120	90	90
140	95	80
160	110	118
180	115	120
200	120	145
220	140	135
240	155	145
260	150	175

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