Dynamic Regression (ARIMA) vs. XGBoost

In the previous article, we mentioned that we were going to compare dynamic regression with ARIMA errors and the xgboost. Before doing that, let’s talk about dynamic regression. Time series modeling, most of the time, uses past observations as predictor variables. But sometimes, we need external variables that affect the target variables. To include thoseContinue reading “Dynamic Regression (ARIMA) vs. XGBoost”

Time Series Forecasting with XGBoost and Feature Importance

Those who follow my articles know that trying to predict gold prices has become an obsession for me these days. And I am also wondering which factors affect the prices. For the gold prices per gram in Turkey, are told that two factors determine the results: USA prices per ounce and exchange rate for theContinue reading “Time Series Forecasting with XGBoost and Feature Importance”

Bootstrapping Time Series for Gold Rush

Bootstrap aggregating (bagging), is a very useful averaging method to improve accuracy and avoids overfitting, in modeling the time series. It also helps stability so that we don’t have to do Box-Cox transformation to the data. Modeling time series data is difficult because the data are autocorrelated. In this case, moving block bootstrap (MBB) shouldContinue reading “Bootstrapping Time Series for Gold Rush”

Approaches to Time Series Data with Weak Seasonality: Dynamic Harmonic Regression

In the previous article, we have tried to model the gold price in Turkey per gram. We will continue to do that to find the best fit for our data. When we chose the KNN and Arima model, we saw the traditional Arima model was much better than the KNN, which is a machine learningContinue reading “Approaches to Time Series Data with Weak Seasonality: Dynamic Harmonic Regression”

Time Series Forecasting: KNN vs. ARIMA

It is always hard to find a proper model to forecast time series data. One of the reasons is that models that use time-series data often expose to serial correlation. In this article, we will compare k nearest neighbor (KNN) regression which is a supervised machine learning method, with a more classical and stochastic process,Continue reading “Time Series Forecasting: KNN vs. ARIMA”

Trend Forecasting Models and Seasonality with Time Series

Gasoline prices always is an issue in Turkey; because Turkish people love to drive where they would go but they complain about the prices anyway. I wanted to start digging for the last seven years’ prices and how they went. I have used unleaded gasoline 95 octane prices from Petrol Ofisi which is a fuelContinue reading “Trend Forecasting Models and Seasonality with Time Series”