Tahmin için Güven Aralıkları

forecast_MET_t tahmin nesnesi yalnızca tahminleri değil, aynı zamanda güven aralıkları adı verilen hata payı hesaplamalarını da içerir. Bu güven aralıkları, hiçbir tahmin mükemmel olmadığından tahminlerimizdeki oynama payını gösterir.

Tahmin forecast_MET_t$mean nesnesinde saklanır. Bu aralığın üst ve alt sınırları da benzer şekilde saklanır. Üst güven aralığının ikinci sütunu 95% güven aralığıdır ve forecast_MET_t$upper[,2] ile erişebilirsin. Alt sınırı almak için upper kelimesini lower ile değiştir.

Bu egzersiz

R ile Ürün Talebi Tahmini

kursunun bir parçasıdır

Kursu Görüntüle

Egzersiz talimatları

Hem üst hem de alt 95% güven sınırlarını xts nesnelerine çevirerek upper ve lower olarak adlandır. Tarih indeksin for_dates olarak saklı.
Bunları tahminin ve doğrulama veri kümesinin grafiğine ekle.

Uygulamalı interaktif egzersiz

Bu örnek kodu tamamlayarak bu egzersizi bitirin.

# Plot the validation data set
plot(MET_t_valid, main = 'Forecast Comparison', ylim = c(4000, 8500))

# Overlay the forecast of 2017
lines(for_MET_t_xts, col = "blue")

# Convert the limits to xts objects
lower <- xts(forecast_MET_t$___[,2], order.by = ___)
upper <- xts(___$___[,___], order.by = for_dates)

# Adding confidence intervals of forecast to plot
lines(lower, col = "blue", lty = "dashed")
lines(___, col = "blue", lty = "dashed")

Kodu Düzenle ve Çalıştır

Bu egzersiz

R ile Ürün Talebi Tahmini

kursunun bir parçasıdır

IntermediárioNível de habilidade

4.8+

Kursa Ücretsiz Başlayın

When it comes to forecasting, time series modeling is a great place to start! You need to forecast out the future values of sales demand and a good baseline approach would be ARIMA models. In this chapter you'll learn how to quickly implement ARIMA models and get good initial forecasts for future product demand.

Exercise 1: Veriyi xts nesnesine yükleme Exercise 2: Veri içe aktarma Exercise 3: Veriyi çizmek / görselleştirmek Exercise 4: ARIMA Zaman Serilerine Giriş Exercise 5: auto.arima() fonksiyonu Exercise 6: auto.arima’yı yorumla Exercise 7: Tahmin ve Değerlendirme Exercise 8: Forecast fonksiyonu Exercise 9: MAPE ve MAE Hesaplama Exercise 10: Tahmini Görselleştirme Exercise 11: Tahmin için Güven Aralıkları

Geçerli Egzersiz

Economic theory has a lot to say about predicting values of demand. Obviously, external factors like price, seasonality, and timing of promotions will drive some aspects of product demand. In this chapter you'll learn about the basics around price elasticity models and how to incorporate seasonality and promotion timing factors into our product demand forecasts.

Exercise 1: Price elasticity Exercise 2: Calculating price elasticity Exercise 3: Interpret results from elasticity Exercise 4: Seasonal / holiday / promotional effects Exercise 5: Visualize holiday / promotion effects Exercise 6: Create holiday / promotional effect variables Exercise 7: Regression for holiday / promotional effects Exercise 8: Significant holiday or promotional effects?Exercise 9: Forecasting with regression Exercise 10: Create future predictor variables Exercise 11: Forecast future values of demand Exercise 12: Visualizing forecasts of regression

Time series models and pricing regressions don't have to be thought of as separate approaches to product demand forecasting. They can be combined! In this chapter you'll learn about two ways of "combining" the information gained in both modeling approaches - transfer functions and forecast ensembling.

Exercise 1: Residuals from regression model Exercise 2: Calculating residuals from regression Exercise 3: Visualizing residuals Exercise 4: Forecasting residuals Exercise 5: auto.arima function Exercise 6: Forecasting residuals with time series Exercise 7: Visualizing residual forecasts Exercise 8: Transfer functions & ensembling Exercise 9: Combining residuals from regression & time series Exercise 10: Visualizing transfer function forecast Exercise 11: Calculating transfer function MAPE and MAE Exercise 12: ARIMA Forecasting Exercise 13: Ensembling of Forecasts

Everything up until this point deals with making individual models for forecasting product demand. However, we haven't taken advantage of the fact that all of these products form a product hierarchy of sales. Products make up regions and regions make up states. How can we ensure that our forecasts reconcile correctly up and down the hierarchy? In this chapter you'll learn about hierarchical forecasting and how to use it to your advantage in forecasting product demand.

Exercise 1: Bottom-Up Hierarchical Forecasting Exercise 2: Build time series forecast for new product Exercise 3: Build regression forecast for new product Exercise 4: Ensemble forecast for new product Exercise 5: Calculate bottom-up forecast for whole region Exercise 6: Top-Down Hierarchical Forecasting Exercise 7: Build time series forecast at regional level Exercise 8: Using average historical proportions Exercise 9: Using proportion of historical averages Exercise 10: Middle-Out Hierarchical Forecasting Exercise 11: Build time series forecast for new region Exercise 12: Top-down forecast for new region Exercise 13: Bottom-up forecast for whole state Exercise 14: Congratulations!