_N_u_m_e_r_i_c _V_e_c_t_o_r_s
	
	     numeric(n=0)
	     as.numeric(x)
	     is.numeric(x)
	
	_D_e_s_c_r_i_p_t_i_o_n:
	
	     numeric creates a real vector of length n.  The vector
	     is filled with zeros.
	
	     as.numeric attempts to coerce its argument to numeric
	     type (either integer or real).
	
	     is.numeric returns TRUE if its argument is of type real
	     or type integer and FALSE otherwise.
	
	_N_o_t_e:
	
	     R has no single precision data type.  All real numbers
	     are stored in double precision format.