0
votes
0answers
6 views

Two age variables in regression

I am performing an hierarchical regression. One of the binary factor variables is if someone is 65 or older (1) or if they are younger than 65 (0). However, I am also applying stratification for age (...
0
votes
0answers
4 views

What is the advantage of sparsity?

In many problems the solution is sparse and the authors of methods usually present it as an advantage. How could one leverage the sparsity in general? Why is an advantage?
0
votes
0answers
3 views

Why is my semivariance so high?

I am using variograms checking for spatial autocorrelation in a resiudal pattern produced by a GLMM-NB. In theory, the semivariance should be bounded between 0 and 1 (that´s what I think at least as I ...
0
votes
0answers
2 views

Correlation between an independent continuous variable and a dependent variable that takes integer values

I have to find a correlation between a numerical continuous dependent variable and a dependent variable which is the 'Number of User's Actions'. As you can figure out this variable gets integer values....
0
votes
0answers
5 views

VAR model with different time period for each series

I am trying to fit a Vector Autoregression model to forecast GDP growth Rate. I have 2 series, monthly GDP growth rate and a monthly economic indicator. For the monthly GDP growth rate, the latest ...
1
vote
2answers
8 views

Finding levels/subsets that will give certain labels with high probabilty

Assume some 1000 data-points of the following pattern X1 X2 Y 2 B 1 1 C 0 6 A 0 3 B 1 3 C 0 where $X_1 \in \{1, 2, 3, 4, 5, 6\}$, $X_2 \in \{A, B, C\}$ ...
0
votes
0answers
5 views

Interpreting adfTest Results in R

I do have a problem interpreting the data set results I got when I ran a adfTest (fUnitRoots package) in R. The test results are: Title: Augmented Dickey-Fuller Test Test Results: ...
0
votes
0answers
7 views

Which of these options are covariance matrices?

Suppose I have covariance matrices $X$ and $Y$. Which of these options are then also covariance matrices? $X+Y$ $X^2$ $XY$ I have a bit of trouble understanding what exactly is needed for ...
0
votes
0answers
5 views

Cross validation for obtaining maximum median SRC Vaue

My dataset is comprised of 5 types of image's sets along with their distortions scores (DMOS) .Let us call the types as Type1,...
0
votes
1answer
16 views

normalisation in k means clustering on percentages and other numerical variables

I have several variables to include in k-means, some of them are percentages (between 0-1) and some of them are numerical variables (positive values). I know normalisation is required when the ...
0
votes
1answer
12 views

Why does -2log-likelihood decrease when you add new variables?

Suppose I'm conducting a study with follow-up survey after N years. Now I want to determine potential risk factors for mortality. I use a model selection procedure and get a table in which the ...
0
votes
0answers
4 views

Model ratio in a one-way repeated measures ANOVA in R?

I've got a dataset with two measures in a group of people, before (pre) and after (post) an intervention. Second measure is always greater than first one. My assumption is that the initial value ...
0
votes
0answers
7 views

Joint distribution of density forecasts

I have a panel data set and I have created a model and finally I have obtained some density forecasts. That is, I run my model for the $y_{it}$ and i obtain predictions for $\hat{y_{i,t+1}}$ , $\hat{...
0
votes
1answer
9 views

Which model is most appropriate to represent this sample data?

I need to determine the most appropriate model to represent the data. It should not be determined from only the $R^2$ value but also from the shape, and need to explain why. What makes one graph ...
1
vote
1answer
13 views

When is cross-sectional data better than panel data?

When is cross-sectional data better than panel data? That might be a weird and strange question: I personally think panel is the best choice but I still want to know if there is some expectations or ...
0
votes
0answers
3 views

Effect size for comparison of two nested models

I want to calculate an effect size for the difference of two structural equation models (model 1 and 2). Model 2 is nested in model 1. For each model I get a $\chi^2$ as measure of fit. Whether the ...
0
votes
0answers
14 views

Why regression output is omitted in Stata?

I am a bit confused of why I get omitted output in my regression results when I know for the fact that all of those dummy combinations are alive and well in my data set: ...
0
votes
0answers
3 views

Adapt function nnetar from package forecast in R

I have a question concerning the forecast package in R. I try to use nnetar to estimate a time series model and run into the problem that my model is too big, i.e. that the number of weights exceeds ...
0
votes
0answers
5 views

Percentile of a data set with more than one variable

I have a data set with more than two variables 1.Number of transactions 2.Money Deposited Now I want to find the 95 percentile of people based on the information.I understand that taking quantiles is ...
0
votes
0answers
9 views

Predicting with function `arima` producing NaN values in R

I am using arima function for intraday forecasting. Data is available for every 15 minute in a day. In the code below, it is working fine except for a few values of ...
0
votes
0answers
2 views

How to split data for LSTM prediction of a vector?

I'm trying to decide how to best split my data to train a LSTM to predict the next time series vector, currently my inputs are 255,30 . So 255 time steps with each containing a vector of length 30 ...
0
votes
0answers
4 views

predict function is underestimating when some polynomials are included in an lmer model

I have been having trouble with the predict function underestimating the predictions from an lmer model with some polynomials. I have scaled data that looks like this: ...
0
votes
1answer
14 views

What do coefficients of auto.arima mean?

After running my auto.arima model I'm getting coefficients ar1, ar2 & sar1. What do these coefficients mean?
0
votes
0answers
5 views

Combine various regression equations of different datasets into One universal regression equation

I am trying to build a regression equation for stocks using various inputs like earnings, price movement, etc. The problem is I will get 100 equations if I try to do it for 100 stocks. How can I ...
0
votes
1answer
24 views

Measuring Accuracy of the SVM based model

I have developed a model which evaluates a user based on how important he is for the organization. For that purpose I have generated 1000 records for 1000 users. Here I have one dependent variable "...
0
votes
0answers
4 views

Similarity measure for clusterings in graphs evolving over time (temporal network)

From what I understand about clusters, they can be obtained from an existing graph at 1 instance of time. But consider the situation of a temporal network, such as a social network, where the graph ...
0
votes
2answers
21 views

T test within data frame in r

I'd like to perform an independant t.test in a data frame ...
0
votes
0answers
10 views

Which algorithm to use

I have a set of devices and I would like to use all of them. I have statistics related to past usage of these devices. Now when a new request comes in I have to predict how the device will be used ...
0
votes
0answers
6 views

KDD dataset - service feature

I am working with the KDD dataset for my evaluation. I have a problem in understanding of what some of the attributes of the service features are. I can't find any documentation about these attributes....
0
votes
0answers
4 views

How to compare the results from two time points in the changed group?

I’m conducting a longitudinal experiment. The purpose of the experiment is to detect relation changes among the members of group (actors). At start time point, $t_0$, I formulated some social network ...
3
votes
0answers
37 views

Was it as valid to perform k-means on a distance matrix as on data matrix (text mining data)?

(This post is a repost of a question I posted yesterday (now deleted), but I've tried to scale back volume of words and simplify what I'm asking) I'm hoping to get some help interpreting a kmeans ...
0
votes
0answers
13 views

Is it possible to conduct ANOVA on paired samples

I have data similar to that (fake values): | Individual | Profession | Software_A | Software_B | |------------|-------------|------------|------------| | A | Teacher | 4.5 | ...
3
votes
1answer
15 views

Distribution of classes in neural network batches

I'm creating a neural network for classifying input data. When using batches, do I need to ensure a somewhat uniform distribution of classes per batch? Or can I simply split up my data in any which ...
0
votes
1answer
11 views

Determining two most similar objects based on multiple variables

I am trying to determine the two most similar years based on a number of environmentally variables. For example, I would like to choose the most similar year to 2015, from the set 1989 to 2016, based ...
0
votes
0answers
6 views

What is the conceptual difference between the marginal variance and the range in the Matérn covariance?

The Matérn covariance kernel is given by: $$ C_\nu(d) = \sigma^2 \frac{2^{1-\nu}}{\Gamma(\nu)}\left(\sqrt{2\nu}\frac{d}{p}\right)^\nu K_\nu\left(\sqrt{2\nu}\frac{d}{p}\right) $$ My question is, what ...
-1
votes
0answers
20 views

Gamma-Poisson distribution, and normal estimate

I'm trying some practice problems and I can't seem to get the same answers as in the solutions. A) Assume that the duration of a student meeting has the gamma distribution with mean 0.5 hours and ...
0
votes
0answers
11 views

bayesglm how to incorporate prior knowledge to improve model

I have downloaded the "University rankings data", available at: https://www.kaggle.com/mylesoneill/world-university-rankings, where the worlds top unis are nked in csv files and I want to take the ...
0
votes
0answers
7 views

RNA-seq: Controlling FDR in multiple contrasts

I'm working on a RNA-seq analysis project and I have come across a statistics problem. I have 3 groups and I need to look for differential expression for each pairwise comparison. Do I control the ...
-1
votes
0answers
16 views

Reference about How to analyze a dataset? [on hold]

I'm having trouble about How to analyze a dataset. I'm a statistician student that already learned a lot of things, but I feel like I didn't know how to apply what I learned properly. What is the ...
0
votes
0answers
16 views

Logistic regression with separated data

How can I find the maximum-likelihood estimation of logistic regression parameters when data is completely separated? By completely separated I mean there exist some $x_{0}$ for which classes are ...
0
votes
0answers
8 views

Regression Table for College GPA [on hold]

Table 1 College GPA for Associate Degree Graduates at a college OLS Regression Coefficients. N=608 Independent Variables Model1 Model 2 Model 3 Model 4 HS GPA 0.204** 0....
0
votes
0answers
13 views

Difference between particle filter (PF) and recurrent neural network (RNN) for time series

Both method are used to estimate time series from data. The question is, when should I use one method or other? Is any advantage to use one instead of the other? I know that in a PF there is a hidden ...
2
votes
1answer
33 views

Arithmetic minus geometric means and the coefficient of variation

This question inspires a further question: For a probability distribution supported on the positive half-line, is the difference between the arithmetic and geometric means bounded by some known ...
0
votes
0answers
3 views

RNA-seq: Controlling FDR in multiple contrasts

I'm working on a RNA-seq analysis project and I have come across a statistics problem. I have 3 groups and I need to look for differential expression for each pairwise comparison. Do I control the ...
0
votes
0answers
6 views

Power Analysis for 1-sample Longitudinal Observational Study

I need to calculate the minimum detectable effect given a known N and desired power. I have a CONTINUOUS EXPOSURE and continuous outcome, each measured twice (baseline + 1 follow-up). If possible, I ...
0
votes
0answers
13 views

clustering based on string variables?

I am working on a project and currently experimenting cluster analysis. The dataset is mainly string variables, and I think my biggest three challenges in the data cleaning phase are the following: ...
0
votes
0answers
5 views

Resources for Determining Value-Added by Parameter Sweeps

I am working on a project that aims to use Design of Experiments to improve our testing process. We are performing tests using a parameter sweeps of numerous input variables (40+). Each input variable ...
0
votes
0answers
15 views

R a priori function association rules between a column

I'm trying to find association rules from a CSV I have which has the folowing columns: Desc which is the description of what was bought and UUID which is the unique ID of each transaction from an ...
0
votes
0answers
7 views

How to compare ordinal variables across groups and time?

I have a short survey that is administered twice (baseline and follow-up, same questions) to a treatment and comparison group. It contains mainly ordinal variables. Here is one example: Overall, how ...

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