Story Name: Smoking and Cancer

Abstract: Government statisticians in England conducted a study of the
relationship between smoking and lung cancer. The data concern 25 occupational
groups and are condensed from data on thousands of individual men. The
explanatory variable is the number of cigarettes smoked per day by men in each
occupation relative to the number smoked by all men of the same age. This smoking
ratio is 100 if men in an occupation are exactly average in their smoking, it is
below 100 if they smoke less than average, and above 100 if they smoke more than
average. The response variable is the standardized mortality ratio for deaths
from lung cancer. It is also measured relative to the entire population of men of
the same ages as those studied, and is greater or less than 100 when there are
more or fewer deaths from lung cancer than would be expected based on the
experience of all English men.

A scatterplot of the data shows a moderately strong linear association, with a
correlation coefficient of 0.716. Residuals from a regression of mortality on
smoking are randomly scattered with no outliers or influential observations.

Reference: Moore, David S., and George P. McCabe (1989). Introduction to the
Practice of Statistics. Original source: Occupational Mortality: The Registrar
General's Decennial Supplement for England and Wales, 1970-1972, Her Majesty's
Stationery Office, London, 1978. Authorization: Description: Data summarizes a
study of men in 25 occupational groups in England. Two indices are presented for
each occupational group. The smoking index is the ratio of the average number of
cigarettes smoked per day by men in the particular occupational group to the
average number of cigarettes smoked per day by all men. The mortality index is
the ratio of the rate of deaths from lung cancer among men in the particular
occupational group to the rate of deaths from lung cancer among all men. Number
of cases: 25 Variable Names:

1.Occupational_Group: Occupational Group
2.Smoking: Smoking index (100 = average)
3.Mortality: Lung cancer mortality index (100 = average)

The Data:

Occupational_Group Smoking Mortality
Farmers, foresters, and fisherman 77 84
Miners and quarrymen 137 116
Gas, coke and chemical makers 117 123
Glass and ceramics makers 94 128
Furnace, forge, foundry, and rolling mill workers 116 155
Electrical and electronics workers 102 101
Engineering and allied trades 111 118
Woodworkers 93 113
Leather workers 88 104
Textile workers 102 88
Clothing workers 91 104
Food, drink, and tobacco workers 104 129
Paper and printing workers 107 86
Makers of other products 112 96
Construction workers 113 144
Painters and decorators 110 139
Drivers of stationary engines, cranes, etc. 125 113
Laborers not included elsewhere 133 146
Transport and communications workers 115 128
Warehousemen, storekeepers, packers, and bottlers 105 115
Clerical workers 87 79
Sales workers 91 85
Service, sport, and recreation workers 100 120
Administrators and managers 76 60
Professionals, technical workers, and artists 66 51