quadFuncDeriv            package:micEcon            R Documentation

_D_e_r_i_v_a_t_i_v_e_s _o_f _a _q_u_a_d_r_a_t_i_c _f_u_n_c_t_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     Calculate the derivatives of a quadratic function.

_U_s_a_g_e:

        quadFuncDeriv( xNames, data, allCoef, allCoefCov = NULL, quadHalf = TRUE  )

_A_r_g_u_m_e_n_t_s:

  xNames: a vector of strings containing the names of the independent
          variables.

    data: dataframe containing the data.

 allCoef: vector containing all coefficients.

allCoefCov: optional covariance matrix of the coefficients.

quadHalf: logical. Multiply the quadratic terms by one half?

_V_a_l_u_e:

     a list of class 'quadFuncDeriv' containing following objects: 

   deriv: data frame containing the derivatives.

variance: data frame containing the variances of the derivatives (only
          if argument 'allCoefCov' is provided).

  stdDev: data frame containing the standard deviations of the
          derivatives (only if argument 'allCoefCov' is provided).

_A_u_t_h_o_r(_s):

     Arne Henningsen ahenningsen@agric-econ.uni-kiel.de

_S_e_e _A_l_s_o:

     'quadFuncEst' and 'quadFuncCalc'

_E_x_a_m_p_l_e_s:

        data( germanFarms )
        # output quantity:
        germanFarms$qOutput <- germanFarms$vOutput / germanFarms$pOutput
        # quantity of variable inputs
        germanFarms$qVarInput <- germanFarms$vVarInput / germanFarms$pVarInput
        # a time trend to account for technical progress:
        germanFarms$time <- c(1:20)

        # estimate a quadratic production function
        estResult <- quadFuncEst( "qOutput", c( "qLabor", "land", "qVarInput", "time" ),
           germanFarms )

        # compute the marginal products of the inputs
        margProducts <- quadFuncDeriv( c( "qLabor", "land", "qVarInput", "time" ),
           germanFarms, estResult$allCoef, estResult$allCoefCov )
        margProducts$deriv

