XL Edge Guide · Correlogram
Correlograms: reading a series' memory
How much does this month resemble last month, or the same month last year? A correlogram answers for every lag at once. It is how you tell whether a series has a trend or a season to remove, which time-series model fits it, and, after fitting, whether the model left anything behind.
What the guide covers
In this guide
- 1The idea: ACF, PACF and the test
- 2Using the ribbon
- 3Reading the block
- 4Step 1: the raw series
- 5Step 2: difference, then identify
- 6Step 3: check the residuals
- 7What chance alone looks like
- 8A pattern guide
- 9Practical advice
- 10Argument reference
What it uses
- Functions
fx.RiskACFλfx.RiskDifferenceλfx.RiskSARIMAResidλ- In the ribbon
- XL Edge tab › Productivity Tools › Stat Tools › Insert Time Series › Test a series › Correlogram (ACF, PACF, Ljung-Box)
- Example workbook
- Monthly sales, the same series as the SARIMA guide. Every number in the guide is read from it.
- Needs
- Excel for Microsoft 365. The workbook carries its own functions in Name Manager, so it calculates with or without XL Edge installed.
Inside
The first four pages
More XL Edge Guides
- BootstrapHow sure are your numbers?
- Confidence EllipseAn interval for two variables at once
- CopulaWhen your inputs move together
- Monte CarloShould we build Plant 2?
- Multivariate Time SeriesSeries that move together: VAR and VECM
- Outliers and LeverageFinding the observations that don't fit
- PortfolioThe efficient frontier in four formulas
- SARIMAForecasting a series with a yearly rhythm