Questions tagged [univariate]

Pertaining to a single variable. Univariate statistics deal with only one variable - e.g. the mean, standard deviation, range etc. Univariate distributions involve only one variable e.g. the univariate normal, uniform etc. distributions.

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86 views

What are other (standard?) distributions that well fit a beta distribution with parameters 3.1 and 1.9?

I have a collection of (200) points that are well-fitted by a (negatively-skewed) beta distribution with parameters $\alpha=3.1$ and $\beta= 1.9$. This is all fine and good, of course, but I am ...
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2k views

Imputation in monthly univariate time series

I have a time series of the amount of apples sold in a specific Region. The time series include monthly values of 10 years (2006-2016). However two months are missing (February 2009 and July 2014). ...
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57 views

Seek tool for univariate exploratory analysis

Looking for a tool to assist with univariate exploratory analysis as an early step in a model building process. Capabilities I’m looking for are to recode or transform the raw predictor variable, x, ...
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664 views

Bootstrapping and hypothesis testing

I got a comment on a paper that I recently submitted. He said, "Pag 7: referring to the “Univariate Analysis” section, bootstrap is not mentioned. This technique is extremely useful when dealing ...
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777 views

Imputation in a univariate time series

I am doing a univariate time series analysis on regional sea-surface temperatures which has missing data, and I am thinking about using the R package, 'imputeTS.' My model is simple, it has MA errors ...
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2answers
2k views

1d optimal clustering

I have the following problem - i have a range of numbers (ie. [1, 5, 7, 8, 15, 29, 100]). I need to cluster them OPTIMALLY (not local optimum as in lloyd algorithm) and better than NP time, minimizing ...
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Do I run a 3-Way ANOVA on SPSS if one of my IV is just there to form a control group?

I'm trying to see what effect different doses of a drug (IV 1) have on the behavior (my dependent variable) of a rodent model; specifically, whether there is a significant change in this behavior ...
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1answer
1k views

Danger of univariate analysis before multiple regression

It's sometimes said (e.g. in this talk) that doing univariate analysis before multiple regression may lead to kicking off useful features and other mistakes. So, my questions are as follows. Are ...
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3k views

Defining a univariate regression

Does the following qualify as a univariate regression? $$y=b_0+b_1x+b_2x^2+\epsilon$$ I fully comprehend the implications of adding regressors and need no background information - a "yes" or "no" ...
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1answer
177 views

Expectations of cosine under von Mises distribution

I'm trying to work out the expectations of a few functions under the von Mises distribution: $ p(\theta \mid \mu, \kappa) = \frac{1}{2\pi I_0(\kappa)} \exp\left\{ \kappa \cos \left( \theta - \mu \...
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29 views

Co-variate contribution to model accuracy in multi-variate analysis

I have implemented a multivariate analysis in R as such: lm1<-lm(Y ~ A + B + C + D + E, data=data, weights = 1/Uncert) I found that the variable A contributes ...
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899 views

Random forest for forecasting univariate time series [closed]

I read few articles on random forest and its implementation in various fields. But I hardly found any literature on its implementation on forecasting univariate time series. Can it be used for ...
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147 views

How to compare three univariate time-series?

I'm new at the StackExchange but got a lot of useful info by reading the posts in the past. Now I'm struggling to find the best way to statistically address my research question and would love to get ...
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1k views

Outlier removal for univariate and multivariate analysis

I have a biological data set on which I would like to do both univariate and multivariate analysis, and try to find correlation of features to a response. Should I remove univariate outliers and do ...
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1answer
615 views

Question about univariate regression

Can we talk about univariate analysis if regression model has two dependent variables? I guess it would be incorrect. However, maybe univariate analysis means that we just analyze Y vs X1 and then Y ...
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1k views

Change point detection with Matlab

I'd like to detect changes in mean in time series data. I've been using R successfully with the ecp (cp3o) and BreakoutDetection libraries. I need to transfer my code from R to Matlab and are therefor ...
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How to interpret the student t statistic in a sas proc univariate output [duplicate]

I ran a proc univariate on a SAS data set and one of the output results was: ...
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1answer
3k views

Variable selection in time series data

I have an econometric dataset, 50 observations of 350 variables. They include things like GDP, unemployment, interest rates and their transformation such as YoY change, log transform, first ...
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211 views

Univariate tests of a multivariate model (MANCOVA)

When running multivariate analysis with covariance, the multivariate tests showed all covariates not to be significant, but the grouping variable was significant. When moving onto univariate tests (...
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1answer
10k views

Univariate cox regression hazard ratio in SPSS

I'm currently doing some analysis for a retrospective cohort study of biomarkers in cancer patients. I've noticed that some papers have utilized univariate cox regression analysis to generate a hazard ...
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271 views

Eta square and effect size in General Linear Model

I have an unbalanced data set that is categorized in 3 different topics. I wanted to see that how these different topics are effecting the data. So I used ...
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1answer
829 views

No significant tests when using Benjamini-Yekutieli multiple testing correction on millions of tests

I am using a univariate filter to reduce the number of features prior to applying a learning algorithm to a huge binary classification dataset (22510066 features x 500 examples). All the features are ...
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60 views

Transforming Series with 2nd Moment Nonstationarity

I am trying to induce stationarity in this series. I have graphed a range-mean plot to detect 1st and 2nd moment nonstationarity. Can anyone suggest a transformation that will remedy the 2nd moment ...
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89 views

Stationarity ⇒ homoscedasticity? [duplicate]

If my data is stationary, can I also write that it is homoscedastic? Does stationarity imply homoscedasticity of the data?
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What type of model should I use? (Time series, univariate, dependent variable is a count)

I have a univariate model in which I am looking to predict the number of articles per week in a newspaper about a protest (count data) by how many arrests of protesters occurred per week. I have 148 ...
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1answer
103 views

Comparing treatment means with lots of zeros

I am trying to compare the means of two treatments on a continuous variable with a lot of zeros in it. I've tried a log(n+1) transformation but that did not get me to a normal distribution. Any ...
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2answers
2k views

Is multiple logistic regression the right choice or should I use univariate logistic regression?

I have a set of data (~ 90 cases) and an outcome of a diagnostic test. I have collected factors that were determined before the test that could predict the outcome of the test. Now some of the data ...
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1answer
626 views

In a matched case-control study, what do I use for hypothesis testing in the descriptive statistics or the “univariate” associations?

I am doing a case-control study with 80 disease cases matched 1:3 to non-diseased controls and examining whether they had a binary exposure prior to developing the disease. I am using multivariable ...
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1answer
763 views

Are the marginal distributions of a multivariate distribution the corresponding univariate distributions?

Are the marginal distributions of a multivariate distribution necessarily the corresponding univariate distributions? For example: Every marginal distribution of a multivariate normal distribution ...
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1answer
95 views

Probability density function within [0,1] with specifiable mode

I needed a probability density function which worked on the interval $[0,1]$, had kind of a bell shape, and had an adjustable mode / peak $p$. I thought of a pdf $f(x|p)$, given by \begin{equation} f(...
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1answer
971 views

Can univariate linear regression be used to identify useful variables for a subsequent multiple logistic regression?

Does the $R^2$ (or some other statistic) from a univariate linear regression tell me anything about how it would work in a logistic model? What if I normalized the data to mean zero? I'm doing ...
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1answer
142 views

Implementation of Univariate logistic regression

For Univariate Linear Regression I can calculate the parameters (And most everything else) from simple sum of squares. Is there a corresponding method for Logistic Regression? Any pointers to code (in ...
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1answer
116 views

In univariate logistic regression, does the scale of values affect the predicted “risk” at a particular value of the independent variable?

I have many datasets representing different populations. Each dataset contains values of an independent variable along with (0/1) representing the occurrence of an undesirable event. I analysed each ...
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1answer
111 views

Given $n$ different univariate non-normal sample sets calculate for a new sample, $x$, which it most likely belongs to [duplicate]

Say you have $n$ different, non-normal, potentially overlapping data sets of samples. Maybe their densities look something like: and you are given a new sample $x$, how would you decide to which of ...
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1answer
475 views

expressing a univariate normal as a multivariate normal

I need to express a univariate normal as a multivariate normal to make certain calculations possible (for example: being able to divide two Gaussian distributions). So, my univariate normal is defined ...
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131 views

Graphical summaries of relationships between univariate distributions

I'd like to review published papers or book chapters (so I could formally refer to them) that graphically illustrate the parametric relationships between univariate distribution families. The papers ...
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447 views

Trend and seasonality tests for a univariate time series

I am working with a batch of about 1000 univariate time series in R . For every time series, I have to perform following tasks , before deciding upon a model be it ARIMA, TAR or Holt Winter's Model ...
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1answer
7k views

Categorize statistical tests into univariate and multivariate methods

I am not sure about the following tests/methods whether they belong to the category of univariate or multivariate tests. Univariate tests/methods: t-test,ANOVA,ANCOVA, univariate linear regression (...
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578 views

Why signs of coefficients change when doing multivariate vs. univariate logit regression? [duplicate]

Excuse my dumb question, but I did an univariate logistic regression where the sign of the coefficient of my variable was negative (and it was significant). Once I have input it into a multivariate ...
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383 views

General linear hypothesis testing in repeated-measures multivariate linear model

In a multivariate linear model $Y = XB + U$, where within-subject (or repeated-measures) factors are coded as simultaneous response variables in $Y$, a general linear hypothesis can be formulated as ...
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1answer
1k views

covariate significant

I'm a bit lost at the results part of my thesis. I have conducted an generalized maximum likelihood (GML) univariate test with Y variable: dependent variable one X variable: independent (consists of 2 ...
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1answer
495 views

How to do Univariate Heteroscedasticity Test

I just wanted to know how to do Heteroscedasticity Test on a Univariate Model? ex: an univariate autoregressive model ex: an univariate ARCH/GARCH model If it is possible, how does one do that in <...
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1answer
1k views

continuous response variable with lots of zero values

I'm trying to determine the effects of four treatments on flowers on the volume of nectar available to pollinators. Problem is, I have about 50% zero volumes across treatment categories. What is the ...
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1answer
7k views

Finding the parameters of bimodal and trimodal univariate distribution with MATLAB

I am rather new to Matlab and never had a lot to do with statistics, so I apologize already for possibly being ignorant of quite a bit of important knowledge. It also would be nice if you could answer ...
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1answer
7k views

Handling outliers in ANOVA

I have a question relative to the correct method to deal with univariate outliers when one has to conduct an ANOVA. Starting with an example, suppose I have two samples of subjects tested on a number ...