This is the pollution data so loved by writers of papers on ridge regression. Source: McDonald, G.C. and Schwing, R.C. (1973) 'Instabilities of regression estimates relating air pollution to mortality', Technometrics, vol.15, 463- 482. Variables in order: PREC   Average annual precipitation in inches JANT   Average January temperature in degrees F JULT   Same for July OVR65  % of 1960 SMSA population aged 65 or older POPN   Average household size EDUC   Median school years completed by those over 22 HOUS   % of housing units which are sound & with all facilities DENS   Population per sq. mile in urbanized areas, 1960 NONW   % non-white population in urbanized areas, 1960 WWDRK  % employed in white collar occupations POOR   % of families with income < $3000 HC     Relative hydrocarbon pollution potential NOX    Same for nitric oxides SO@    Same for sulphur dioxide HUMID  Annual average % relative humidity at 1pm MORT   Total age-adjusted mortality rate per 100,000