normalEqn <- function(X, y) {
  
  #    Computes the closed-form solution to linear regression 
  #
  #    theta <- normalEqn(X, y) computes the closed-form solution to linear 
  #    regression using the normal equations.
  
  #  ====================== YOUR CODE HERE ======================
  #  Instructions: Complete the code to compute the closed form 
  #                solution to linear regression and put the result
  #                in theta.
  #  
  #  Hint: Use the function ginv in package MASS to compute 
  #        the inverse of a matrix
  
  
  
  #  ============================================================
  
  return(theta)
}