sd                   package:stats                   R Documentation

_S_t_a_n_d_a_r_d _D_e_v_i_a_t_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     This function computes the standard deviation of the values in
     'x'. If 'na.rm' is 'TRUE' then missing values are removed before
     computation proceeds. If 'x' is a matrix or a data frame, a vector
     of the standard deviation of the columns is returned.

_U_s_a_g_e:

     sd(x, na.rm = FALSE)

_A_r_g_u_m_e_n_t_s:

       x: a numeric vector, matrix or data frame. An object which is
          not a vector, matrix or data frame is coerced (if possible)
          by 'as.vector'.

   na.rm: logical. Should missing values be removed?

_D_e_t_a_i_l_s:

     Like 'var' this uses denominator n - 1.

     The standard deviation of a zero-length vector (after removal of
     'NA's if 'na.rm = TRUE') is not defined and gives an error. The
     standard deviation of a length-one vector is 'NA'.

_S_e_e _A_l_s_o:

     'var' for its square, and 'mad', the most robust alternative.

_E_x_a_m_p_l_e_s:

     sd(1:2) ^ 2