Refers generally to making substantive conclusions from the results of a statistical analysis.

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3 views

Does the confidence measure of a SVM have a meaning that can be compared across different models?

Suppose I train two SVMs ($m_1$ and $m_2$) on two different (potentially unrelated) problems. I then present datum $d_1$ to model $m_1$ and it outputs a vector $v_1$ of probabilities over the space ...
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33 views

How to use LDA results for prediction? And how to assess model fit?

I am trying to understand how to interpret the results I get from LDA. Running from the iris dataset in R, I can see the discriminant coefficients are in the model and then I can plot the model to ...
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36 views

Path analysis and multiple mediators

I have a study with two potential mediators: M1 and M2. I obtain a main effect of my independent variable X on the dependent variable Y. Similarly, I obtain an effect of X on M1, but I do not have an ...
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1answer
22 views

Time series regression coefficient interpretation with differenced independent variable

I'm working on a project on time series regression. The independent variable was non stationary so I took first differences to stationarize it. Now when I regress it against the dependent variable the ...
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1answer
48 views

Multiple regression in R results different to simple linear regression? [duplicate]

Hi I am having trouble acquiring the final results for presentation. The results from a multiple regression are different to my results in a simple linear regression. For example, the multiple ...
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3answers
170 views

Interpretation of the variance of a slope

If I have a simple regression model: $$Y = \beta_1 + \beta_2(\text{income}) + \varepsilon$$ I can calculate the $\text{Var}(\hat{\beta_2})$ quite easily with a formula. However, what is the ...
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25 views

The statistical coffee test

I have had a couple of courses in mathematics, and two in basic statistics. over the last few days I have pondered on how to perform the best possible test of coffee brands, using my knowledge of ...
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8 views

Assessing variable importance in generalized additive models (GAM)

In a linear model, it's easy to assess the importance of each explanatory variable. If the assumptions of the model are met, given two explanatory variables $x_1$ and $x_2$, both with a regression ...
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22 views

Probit Model: Interpretation of marginal effects if explanatory variables are proportions

How do I interpret the marginal effect of an explanatory variable that is a proportion in a probit model? For example if I get a marginal effect of 0.8 does this mean that if the proportion increases ...
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29 views

Comparison of different impulse response functions (IRFs)

I try to compare the impulse responses from different studies. However, I am not sure if my conclusions are correct. This is my problem: Two studies that use monthly data report the responses of ...
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25 views

How do I interpret the random intercepts of a multilevel mixed-effects model?

I am using a three-level mixed-effects model in which: individuals (level 1) are nested in primary sampling units (PSUs) or enumeration areas (level 2) which in turn are nested in countries ...
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1answer
53 views

Interpreting the change in two logs in a regression

If I have a log-log regression, like: $\ln(\text {Price}) = b_0 + b_1 \times (\Delta \ln (\text{emp}))$ Where $\Delta(\ln (\text{emp})) = \ln(\text{employment growth_year2}) - \ln(\text{employment ...
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36 views

Back-transform coefficient from linear mixed model with log-transformed response

I ran a linear mixed model (lme4::lmer in R) with a log-transformed (base 2) response, and predictors were not transformed. I want to back-transform my coefficients to make a statement about effect ...
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0answers
41 views

How to interpret Q-Q plots by comparing axis and the plotted points?

One can interpret QQ plots by considering the values read from the axes compared for given plotted points. And if the data were well described by a normal distribution, the values should be about the ...
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0answers
13 views

Building interaction terms with dummy coded categorical predictors with more than 2 categories

I would like to perform a linear regression on a data set with a continuous DV (score). I do not understand how to interpret interactions made with the dummy coded variables that have a reference ...
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1answer
34 views

OLS interpretation - if Y increases due to X increasing, can I say that if X decreases, Y will decrease with the same magnitude?

$$ \ln(y)=b + 0.25\ln(X) + \epsilon $$, i.e. for $10\%$ increase in $X$, we observe about $2.5\%$ increase in $Y$. Can I claim that if I reduce $X$ by $10\%$, then Y will drop $2.5\%$? Can such ...
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1answer
19 views

Interaction between continous variables

I have a question regarding the interpretation of a interaction term between two continous variables that are temperature and time. I did not center these two variable and I inserted directly the ...
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0answers
9 views

Investigate clusters of outcome variables in a study and verify whether stratification for an exposure changes the clusters

We have a study in which we have a number of outcomes (~30) and big number of observations/patients (> 1000) and we tested the effect of a certain exposure on the probability of these outcomes. For ...
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1answer
33 views

Interpretation of interaction variable when base variable is insignificant

I am investigating the effect of Indian service imports on U.S. service employment, using a balanced panel data set. The employment data are state-level for 5 different business service sectors. In ...
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1answer
30 views

Two interpretations of significant negative intercept: which is correct?

I applied a linear mixed model on binomial data. In short, I have 2 binomial independent variables: Prime (DO or PO) and Language (English L1 and English L2), and my dependent variable is DO use (DO ...
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0answers
23 views

Interpretation of graph of pairwise concordance correlations

I have graphed pairwise concordance correlation coefficients (CCC) where a value of -1 should be complete disagreement, 1 perfect agreement, and values around 0.4 "good to fair". My results looks like ...
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0answers
11 views

Orthogonal polynomial coding

Is there a "formal" interpretation of parameters associated to orthogonal polynomial columns when having a regression on ordered categorical variables? I mean: you can interpret the $\beta_j$ as $E[Y ...
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0answers
13 views

“Cooking ingredients” problem

I have a problem like this. Suppose I have 3 persons, A,B, and C to make cookies with 3 basics ingredients, flour, egg, and water. The recipe to make cookie is unknown but we need too determine the ...
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0answers
13 views

Negative binomial regression - compare size of effect

I am analyzing the influence of grades and work experience (measured in month) on the number of invitations to an job interview. sice number of invitations is a count variable i am running a negative ...
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11 views

Coefficient - different specifications - significant vs not significant - interpretation [duplicate]

for my bachelor thesis I am analyzing the influence of grades (G) and work experience (WE) on the probability to get a job (J). I have three specifications (simplyfied they look like this): J = ...
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17 views

Centering in the presence of interactions with categorical predictors?

I understand that always scaling covariates prior to regression analysis is controversial advice. See for example Andrew Gelman's blogpost and comments, or many crossvalidated questions such as this ...
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18 views

How to demonstrate a tradeoff between two desirable but incompatible metrics/features?

I'm trying to understand a tradeoff that came up to me when I'm studying an algorithm used to distribute a load in a distributed system. The tradeoff involves network communication and make span. ...
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33 views

A question on Multinomial Regression

Assume an experiment with 6 outcomes, dubbed A, B, C, D and E. For outcome A, there are Na subject, for B there are Nb subject and so on. Now assume we fit a multinomial regression using a Bayesian ...
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39 views

Interpretation of vector error correction model in R

I estimated a VECM using the following code: ...
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0answers
35 views

Varying lengths of eigenvectors on a PCA biplot

I'm conducting a PCA in Matlab on standardized variables. My goal is to interpret angles = loadings, correlations bw. variables and PC-axis directions = vectors point to the direction of the ...
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1answer
37 views

What does it mean if none of the principal components explains the majority of the variance?

I have a dataset with 1228 peaks and 15 features, and I am trying to use PCA analysis to reduce dimensionality and discover the most useful features describing the dataset. When I ran PCA analysis ...
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1answer
42 views

Residuals colors of the mosaic plot are all dark. Implies?

I am working on interpreting the nature of the association of a contingency table. I tried to provide a mosaic plot of the data that I have and it resulted to Can anyone help me interpret this data ...
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1answer
49 views

Anova of metric items: SPSS and R display different square-sums and F-values. Which is the better philosophy?

With a small book-exercise with four metric variables on 10 cases (one dependent/outcome, three independent/predictor) I ran linear regression in SPSS and ...
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27 views

Understanding model output with categorical data

I can't figure out the format of the output below. I'm confused as to which P value is related to what. It seems to be very counter-intuitive. Input and output: Here is a sample of the data showing ...
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27 views

Finding causality and/or correlation within a dataset [closed]

I have 3 data sets (3 days) which I need to analyze. My goal is to show what the interaction between aerosols and plants is, if and how they impact on plant photosynthesis. These are my variables: ...
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0answers
12 views

Interpreting values of the Gini index?

I'm wondering if the Gini index has a straightforward interpretation. I'd like to make these values more tangible to those unfamiliar with them and to improve my own understanding. Is there an ...
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0answers
29 views

What does the product of the covariance matrix by a metric matrix actually mean?

Let be the following data matrice: $$A=\begin{bmatrix} 1 & 0 & 0 \\ 0 & 0 & 1 \\ 0 & 1 & 2 \\ 2 & 1 & 1 \\ 1 & 1 & 0 \\ 2 & 3 ...
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17 views

How to interpret an ARMAX table

How to interpret the significant coefficients in the ARMAX on the dependent variable, oil price (Oil)? The data are returns. The coefficients on Technology ...
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1answer
35 views

Interpreting explanatory power of linear regression output

Here I have linear regression output from which I need to figure out: Which one of nids$hhincome (household income, numeric) and ...
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0answers
7 views

Interpretation of Mantel r correlations

I am using mantel in R package Ecodist to perform a series of partial mantel tests. I am examining the correlation between a species composition (Bray-curtis ...
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2answers
209 views

Is prediction the 'golden criterion' to judge the ability of statisticans?

I was reading Faraway's textbook linear models with R (1st edition) last weekend. Faraway had a chapter called "Statistical Strategy and Model Uncertainty". He described (page 158) that he ...
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1answer
57 views

Interpretation of two glm model summaries

I am using the Titanic dataset to understand glm model. These are the two models, ...
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0answers
19 views

How to analyze the odds ratios in general linear mixed models for binary outcome?

I am using lmer4 library in R. I have a simple mixed effect model with one fixed factor and one random factor. These are my results: ...
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0answers
16 views

How to interpret the coefficients of linear regression when all the variables are ordinal with different categories.

I have a linear regression where my dependent variable is ordinal with 10 categories. One of the independent variable is ordinal with 4 categories and the other independent variable is ordinal with 6 ...
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0answers
23 views

Interpreting Spatio-Temporal Variograms

I've got spatio-temporal disease data at the county/annual level for 2000-2014. I'm analyzing it to try to pull out temporal variations in disease incidence and was told that I should generate a ...
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40 views

Interpretation of Principal Component Analysis Results

I have a 13-item, 5-point Likert-type scale that I have put together from similar questions used in the literature (n = 96). What is the best way to analyse my scale data? Step-by-step, what I have ...
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0answers
19 views

Interpretation of results from Johansen's co-integration test

I am not able to interpret the following result output for gretl for co-integration: Rank $\ $ Eigenvalue $\ \ $ Trace test $\ \ $ p-value $\ \ $ Lmax test $\ $ p-value 0 $\ \ \ \ \ \ \ $ 0.032753 ...
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2answers
44 views

Can mixed models can be used to study longitudinal changes in independent variable?

I have a R dataframe that contains prices and many metadata fields from books published between 1700 and 1800: ...
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1answer
29 views

How to understand mutual Granger causality

As stated in title, when we have a time series model of two variables, e.g x and y, and conduct the Granger causality test to examine the "causal relationship" between two variables, we can be in a ...