#  x15.txt
#
#  Reference:
#
#    Helmut Spaeth,
#    Mathematical Algorithms for Linear Regression,
#    Academic Press, 1991,
#    ISBN 0-12-656460-4.
#
#    S Weisberg,
#    Applied Linear Regression,
#    New York, 1980, pages 32-33.
#
#  Discussion:
#
#    For one year, the consumption of petrol was measured in 48 states.
#    The relevant variables are the petrol tax, the average
#    income per capita, the number of miles of paved highway, and
#    the proportion of the population with driver's licenses.
#
#    There are 48 rows of data.  The data include:
#
#      I,  the index;
#      A1, the petrol tax;
#      A2, the per capita income;
#      A3, the miles of paved highway;
#      A4, the proportion of drivers;
#      B,  the consumption of petrol.
#
#    We seek a model of the form:
#
#      B = A1 * X1 + A2 * X2 + A3 * X3 + A4 * X4.
#
6 columns
48 rows
Index
Petrol tax (cents per gallon)
Average income (dollars)
Paved Highways (miles)
Proportion of population with driver's licenses
Consumption of petrol (millions of gallons)
 1   9.00  3571   1976  0.5250  541
 2   9.00  4092   1250  0.5720  524
 3   9.00  3865   1586  0.5800  561
 4   7.50  4870   2351  0.5290  414
 5   8.00  4399    431  0.5440  410
 6  10.00  5342   1333  0.5710  457
 7   8.00  5319  11868  0.4510  344
 8   8.00  5126   2138  0.5530  467
 9   8.00  4447   8577  0.5290  464
10   7.00  4512   8507  0.5520  498
11   8.00  4391   5939  0.5300  580
12   7.50  5126  14186  0.5250  471
13   7.00  4817   6930  0.5740  525
14   7.00  4207   6580  0.5450  508
15   7.00  4332   8159  0.6080  566
16   7.00  4318  10340  0.5860  635
17   7.00  4206   8508  0.5720  603
18   7.00  3718   4725  0.5400  714
19   7.00  4716   5915  0.7240  865
20   8.50  4341   6010  0.6770  640
21   7.00  4593   7834  0.6630  649
22   8.00  4983    602  0.6020  540
23   9.00  4897   2449  0.5110  464
24   9.00  4258   4686  0.5170  547
25   8.50  4574   2619  0.5510  460
26   9.00  3721   4746  0.5440  566
27   8.00  3448   5399  0.5480  577
28   7.50  3846   9061  0.5790  631
29   8.00  4188   5975  0.5630  574
30   9.00  3601   4650  0.4930  534
31   7.00  3640   6905  0.5180  571
32   7.00  3333   6594  0.5130  554
33   8.00  3063   6524  0.5780  577
34   7.50  3357   4121  0.5470  628
35   8.00  3528   3495  0.4870  487
36   6.58  3802   7834  0.6290  644
37   5.00  4045  17782  0.5660  640
38   7.00  3897   6385  0.5860  704
39   8.50  3635   3274  0.6630  648
40   7.00  4345   3905  0.6720  968
41   7.00  4449   4639  0.6260  587
42   7.00  3656   3985  0.5630  699
43   7.00  4300   3635  0.6030  632
44   7.00  3745   2611  0.5080  591
45   6.00  5215   2302  0.6720  782
46   9.00  4476   3942  0.5710  510
47   7.00  4296   4083  0.6230  610
48   7.00  5002   9794  0.5930  524