Week_1_Assignment_ITCS_6500

docx

School

University of North Carolina, Charlotte *

*We aren’t endorsed by this school

Course

6500

Subject

Statistics

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by arkasuper

How Can Time-Series Data Be Declared As Stationery? Show drafts Declaring time-series data as stationary doesn't involve a formal "declaration" but rather analyzing the properties of the data to see if it meets certain criteria . A time series is considered stationary if its statistical properties (like mean, variance, autocorrelation) remain constant over time . This means the patterns and relationships within the data don't change based on when the data was collected. Here's how you can assess if your time-series data is stationary: Visual Inspection:  Plots: Look for trends, seasonality, or sudden changes in the level of the data over time. Stationary data tends to fluctuate around a constant mean with no obvious trends or seasonality.  Autocorrelation functions (ACF) and partial autocorrelation functions (PACF): These plots show how correlated the data is with its past values. In stationary data, these functions decay quickly to zero, indicating that past values have less and less influence on future values. Statistical Tests:  Unit root tests: These tests, like the Augmented Dickey-Fuller (ADF) test, formally assess the presence of a unit root (non-stationarity) in the data.  Stationarity tests: Other tests, like the KPSS test, directly test for stationarity by checking if the data resembles a random walk. Transformations: If your data appears non-stationary, you can often transform it to make it stationary . Common transformations include:  Differencing: Subtracting previous values from the current value to remove trends.  Logarithmic transformation: Useful for data with skewed distributions.  Seasonal differencing: Accounting for seasonal patterns by differencing across seasonal lags. Important points to remember:  Stationarity is an assumption for many time-series a

Discover more documents: Sign up today!

Unlock a world of knowledge! Explore tailored content for a richer learning experience. Here's what you'll get: