multivariate analysis
tandx
BytheMarkovian assumption forlatent state vectors, the Hessian matrix is tri-block diagonal. To facilitate convergence, we initialize the Newton update with a smoothing estimate bylocalGaussian approximation. Theforwardfiltering foradynamic Poisson modelhas been previously described (Eden etal., 2004), and we use anadditional backward pass tosmooth (Rauchetal.,1965). Without constraints, the sampling ofh(j), g(j) and ฯ2(j) is the same as shown previously. The update of A(j), b(j) and Q(j) is the standard multivariate Bayesian linear regression.
A Generalized Similarity U Test for Multivariate Analysis of Sequencing Data
Summary: Sequencing-based studies are emerging as a major tool for genetic association studies of complex diseases. These studies pose great challenges to the traditional statistical methods because of the high-dimensionality of data and the low frequency of genetic variants. Moreover, there is a great interest in biology and epidemiology to identify genetic risk factors contributed to multiple disease phenotypes. The multiple phenotypes can often follow different distributions, which brings an additional challenge to the current statistical framework. In this paper, we propose a generalized similarity U test, referred to as GSU. GSU is a similarity-based test that can handle high-dimensional genotypes and phenotypes. We studied the theoretical properties of GSU, and provided the efficient p-value calculation for association test as well as the sample size and power calculation for the study design. Through simulation, we found that GSU had advantages over existing methods in terms of power and robustness to phenotype distributions. Finally, we used GSU to perform a multivariate analysis of sequencing data in the Dallas Heart Study and identified a joint association of 4 genes with 5 metabolic related phenotypes. Key words: Weighted U Statistic; Sequencing Study; Non-parametric Statistics. 1. Introduction Genome-wide association studies (GW AS) have made substantial progress in discovering common genetic variants associated with complex diseases. Despite such success, a large proportion of heritability of complex diseases remains unexplained.
Multivariate Analysis of Gut Microbiota Composition and Prevalence of Gastric Cancer
Shankarnarayanan, Aadhith, Gangopadhyay, Dheeman, Alzaatreh, Ayman
The global surge in the cases of gastric cancer has prompted an investigation into the potential of gut microbiota as a predictive marker for the disease. The alterations in gut diversity are suspected to be associated with an elevated risk of gastric cancer. This paper delves into finding the correlation between gut microbiota and gastric cancer, focusing on patients who have undergone total and subtotal gastrectomy. Utilizing data mining and statistical learning methods, an analysis was conducted on 16S-RNA sequenced genes obtained from 96 participants with the aim of identifying specific genera of gut microbiota associated with gastric cancer. The study reveals several prominent bacterial genera that could potentially serve as biomarkers assessing the risk of gastric cancer. These findings offer a pathway for early risk assessment and precautionary measures in the diagnosis of gastric cancer. The intricate mechanisms through which these gut microbiotas influence gastric cancer progression warrant further investigation. This research significantly aims to contribute to the growing understanding of the gut-cancer axis and its implications in disease prediction and prevention.
Introduction to Univariate, Bivariate, and Multivariate Analysis
Univariate: When there is just one variable in the data and no mention of causes, effects, or causal links. For instance, the researcher may want to count the number of males and girls in a school when conducting a survey. The data, in this case, would just show a number, i.e., a variable and amount. The main goal of univariate data is to describe the data using mean, median, variance, mode, dispersion, range, standard deviation, etc. to identify patterns within the data. Bivariate: When the dataset contains two variables and researchers aim to undertake a comparison between the two datasets then the bivariate analysis is the right technique.
Latent Temporal Flows for Multivariate Analysis of Wearables Data
Amiridi, Magda, Darnell, Gregory, Jewell, Sean
Increased use of sensor signals from wearable devices as rich sources of physiological data has sparked growing interest in developing health monitoring systems to identify changes in an individual's health profile. Indeed, machine learning models for sensor signals have enabled a diverse range of healthcare related applications including early detection of abnormalities, fertility tracking, and adverse drug effect prediction. However, these models can fail to account for the dependent high-dimensional nature of the underlying sensor signals. In this paper, we introduce Latent Temporal Flows, a method for multivariate time-series modeling tailored to this setting. We assume that a set of sequences is generated from a multivariate probabilistic model of an unobserved time-varying low-dimensional latent vector. Latent Temporal Flows simultaneously recovers a transformation of the observed sequences into lower-dimensional latent representations via deep autoencoder mappings, and estimates a temporally-conditioned probabilistic model via normalizing flows. Using data from the Apple Heart and Movement Study (AH&MS), we illustrate promising forecasting performance on these challenging signals. Additionally, by analyzing two and three dimensional representations learned by our model, we show that we can identify participants' $\text{VO}_2\text{max}$, a main indicator and summary of cardio-respiratory fitness, using only lower-level signals. Finally, we show that the proposed method consistently outperforms the state-of-the-art in multi-step forecasting benchmarks (achieving at least a $10\%$ performance improvement) on several real-world datasets, while enjoying increased computational efficiency.
Multivariate Analysis using SAS
As a first method, it gives you a good idea about the level of multicollinearity involved and how much the two specified sets relate to themselves and each other. Do not forget -- CCA is mainly used for prediction, not interpretation. And the last of the trio is the Discriminant Function Analysis (DFA) which is used to answer the question: Can a combination of variables be used to predict group membership? Because, if a set of variables predicts group membership, it is also connected to that group. DFA is a dimension-reduction technique related to Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA).
A selective review of sufficient dimension reduction for multivariate response regression
Dong, Yuexiao, Soale, Abdul-Nasah, Power, Michael D.
We review sufficient dimension reduction (SDR) estimators with multivariate response in this paper. A wide range of SDR methods are characterized as inverse regression SDR estimators or forward regression SDR estimators. The inverse regression family include pooled marginal estimators, projective resampling estimators, and distance-based estimators. Ordinary least squares, partial least squares, and semiparametric SDR estimators, on the other hand, are discussed as estimators from the forward regression family.
Machine Learning for Time-Series with Python
The term time-series analysis (TSA) refers to the statistical approach to time-series or the analysis of trend and seasonality. It is often an ad hoc exploration and analysis that usually involves visualizing distributions, trends, cyclic patterns, and relationships between features, and between features and the target(s). More generally, we can say TSA is roughly exploratory data analysis (EDA) that's specific to time-series data. This comparison can be misleading however since TSA can include both descriptive and exploratory elements. Let's see quickly the differences between descriptive and exploratory analysis: Therefore, TSA is the initial investigation of a dataset with the goal of discovering patterns, especially trend and seasonality, and obtaining initial insights, testing hypotheses, and extracting meaningful summary statistics.
Statistical Depth Meets Machine Learning: Kernel Mean Embeddings and Depth in Functional Data Analysis
Wynne, George, Nagy, Stanislav
Functional data analysis (FDA) concerns the study of observations that can be represented as functions, often residing in an infinite-dimensional space. In the recent decades, FDA saw remarkable progress, with many theoretical and practical problems successfully resolved. Often, however, statistical concepts used in finite-dimensional spaces do not readily generalise to random functions. As a result, alternative definitions and desired properties have to be used [80, 27, 46, 47]. An example of a prominent tool of multivariate analysis that is difficult to generalise to functional data is statistical depth. Developed in the 1980s, statistical depth is an umbrella term for methods introducing orderings, ranks, and by extension, nonparametric statistical inference, to multivariate and more complex datasets.