Sparse Principal Component Analysis (PCA)

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10 Questions

What is the defining characteristic of exponential growth?

A quantity increases at a rate proportional to its current value

Which model is used to capture and predict changing volition in time series data?

GARCH

What is the purpose of differencing in the ARIMA model?

To make the time series stationary

What is the primary application of Vector Auto Regression (VAR) models?

Forecasting multiple time series simultaneously

What is Granger causality used for?

To determine if one time series can predict another

What is the characteristic of co-integrated variables?

A linear combination of them is stationary

What is the primary application of Vector Error Correction Model (VECM)?

Analyzing and forecasting the long-term and short-term dynamics of co-integrated variables

What is the difference between ARIMA and ARMA models?

ARIMA is used for non-stationary time series, while ARMA is used for stationary time series

Which model is a stochastic approach to time series modeling?

ARIMA

What is the characteristic of exponential decay?

A quantity decreases at a rate proportional to its current value

Study Notes

Dimensionality Reduction

  • Sparse Principal Component Analysis (Sparse PCA) is a variant of traditional Principal Component Analysis (PCA) that introduces sparsity constraints on the principal components.
  • Sparse PCA provides a more interpretable set of principal components, performs feature selection and dimensionality reduction simultaneously, and is more efficient than regular PCA in handling high-dimensional data.
  • Factor Analysis (FA) is a statistical technique used for dimensionality reduction and exploring the underlying structure in a dataset, assuming that observed variables are influenced by latent factors.

Clustering

  • Two-steps clustering is a clustering algorithm used to group data points into clusters based on their similarities, particularly useful for dealing with large datasets or data sets containing both categorical and continuous variables.
  • Bi-clustering, also known as block clustering or co-clustering, is a data mining technique that allows simultaneous clustering of both rows and columns of a matrix, particularly useful for identifying groups of data items that exhibit consistent patterns across both rows and columns.
  • Latent clustering, also known as Latent Class Cluster Analysis (LCCA), is a powerful technique that can uncover hidden structures in data by identifying latent subgroups or classes.
  • K-means clustering is a popular and powerful unsupervised machine learning algorithm that can be used to group data points into distinct clusters based on their similarities.

Time Series Analysis

  • Stochastic approach is a type of time series analysis that involves modeling the future behavior of a time series as uncertain and can be modeled using probability distributions.
  • Time series decomposition is a technique used to break down a time series into its underlying component, typically trend, seasonality, and residual components.
  • Linear trend model is a deterministic approach used to identify and model trends in time series, assuming that the time series follows a straight line trend over time.
  • Exponential growth or decay models are powerful tools for analyzing and forecasting a wide range of real-world processes that exhibit proportional rates of change over time.

Time Series Models

  • ARIMA (Autoregression Integrated Moving Average) is a stochastic approach used to model time series data, combining autoregression and moving average.
  • GARCH model (Generalized Autoregression Conditional Heteroskedasticity) is used to capture and predict changing volition in time series data.
  • VAR (Vector Auto Regression) is a multivariate time series model used to capture the linear interdependencies among multiple time series.
  • VECM (Vector Error Correction Model) is a multivariate time series model used to analyze and forecast the long-term and short-term dynamics of co-integrated variables.

Sparse PCA introduces sparsity constraints on principal components, finding sparse linear combinations of original features, useful in high-dimensional data scenarios.

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