gravity package:boot R Documentation _A_c_c_e_l_e_r_a_t_i_o_n _D_u_e _t_o _G_r_a_v_i_t_y _D_e_s_c_r_i_p_t_i_o_n: The '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' data frame contains the data from all eight experiments. The 'grav' data frame contains the data from the experiments 7 and 8. The data are expressed as deviations from 980.000 in centimetres per second squared. _U_s_a_g_e: gravity _F_o_r_m_a_t: This data frame contains the following columns: '_g' The deviation of the estimate from 980.000 centimetres per second squared. '_s_e_r_i_e_s' A factor describing from which experiment the estimate was derived. _S_o_u_r_c_e: The data were obtained from Cressie, N. (1982) Playing safe with misweighted means. _Journal of the American Statistical Association_, *77*, 754-759. _R_e_f_e_r_e_n_c_e_s: Davison, A.C. and Hinkley, D.V. (1997) _Bootstrap Methods and Their Application_. Cambridge University Press.