micEcon (version 0.5-6)

quadFuncDeriv: Derivatives of a quadratic function

Description

Calculate the derivatives of a quadratic function.

Usage

quadFuncDeriv( xNames, data, coef, coefCov = NULL, quadHalf = TRUE  )

Arguments

xNames

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

data

dataframe containing the data.

coef

vector containing all coefficients.

coefCov

optional covariance matrix of the coefficients.

quadHalf

logical. Multiply the quadratic terms by one half?

Value

• 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 coefCov is provided).
• stdDev
  data frame containing the standard deviations of the derivatives (only if argument coefCov is provided).

See Also

quadFuncEst and quadFuncCalc

Examples

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, coef( estResult ), vcov( estResult ) )
   margProducts$deriv