For this model, we decided to use Gauss-Markov theorem to understand whether it works with economy of the Republic of Chad. This theorem states that the ordinary least squares (OLS) estimator has the lowest sampling variance within the class of linear unbiased estimators, if the errors in the linear regression model are uncorrelated, have equal variances and expectation value of zero. At the same time, we will apply a regression analysis method based on time series data. These will consist of annual observations of GDP, final consumption expenditure, foreign direct investment (FDI), and government spending.
In the beginning, the main idea was to collect reliable and relevant data about such components of the Republic of Chad as GDP, domestic consumption, foreign direct investment and governmental spending.