function error = lsqError(parameter, x, y)
% Objective function for fitting a linear equation to data.
%
% Arguments: parameter, vector containing slope and intercept 
%                       as the 1st and 2nd element 
%            x, vector of the input values
%            y, vector of the corresponding measured output values
%
% Returns: the estimation error in terms of the mean sqaure error

  y_est = x .* parameter(1) + parameter(2);
  error = meanSquareError(y, y_est);
end