gravity data frame has 81 rows and 2 columns.
The grav data set has 26 rows and 2 columns.
Between May 1934 and July 1935, the National Bureau of Standards in Washington D.C. conducted a series of experiments to estimate the acceleration due to gravity, g, at Washington. Each experiment produced a number of replicate estimates of g using the same methodology. Although the basic method remained the same for all experiments, that of the reversible pendulum, there were changes in configuration.
The gravity dataframe contains the
data from all eight experiments. The grav dataframe contains the data from
the experiments 7 and 8. The data are expressed as deviations from
980.000 in centimetres per second squared.
data(gravity)Cressie, N. (1982) Playing safe with misweighted means. Journal of the American Statistical Association, 77, 754--759.