Story Name: Alcohol and Tobacco

Abstract: Data from a British government survey of household spending may be used
to examine the relationship between household spending on tobacco products and
alcholic beverages. A scatterplot of spending on alcohol vs. spending on tobacco
in the 11 regions of Great Britain shows an overall positive linear relationship
with Northern Ireland as an outlier. Northern Ireland's influence is illustrated
by the fact that the correlation between alcohol and tobacco spending jumps from
.224 to .784 when Northern Ireland is eliminated from the dataset.

This dataset may be used to illustrate the effect of a single influential
observation on regression results (i.e., an outlier). In a simple regression of alcohol spending on
tobacco spending, tobacco spending does not appear to be a significant predictor
of tobacco spending. However, including a dummy variable that takes the value 1
for Northern Ireland and 0 for all other regions results in significant
coefficients for both tobacco spending and the dummy variable, and a high
R-squared.

Datafile Name: Alcohol and Tobacco

Reference: Moore, David S., and George P. McCabe (1989). Introduction to the
Practice of Statistics, p. 179. Original source: Family Expenditure Survey,
Department of Employment, 1981 (British official statistics) Authorization:
contact authors Description: Average weekly household spending, in British
pounds, on tobacco products and alcoholic beverages for each of the 11 regions of
Great Britain. Number of cases: 11 Variable Names:

1.Region: Region of Great Britain
2.Alcohol: Average weekly household spending on alcoholic beverages in pounds
3.Tobacco: Average weekly household spending on tobacco products in pounds

The Data:

Region Alcohol Tobacco
North 6.47 4.03
Yorkshire 6.13 3.76
Northeast 6.19 3.77
East Midlands 4.89 3.34
West Midlands 5.63 3.47
East Anglia 4.52 2.92
Southeast 5.89 3.20
Southwest 4.79 2.71
Wales 5.27 3.53
Scotland 6.08 4.51
Northern Ireland 4.02 4.56