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

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14 views

How do one interpret the results of wilcoxon-mann-whitney test in SAS?

I have done the Wilcoxon test in SAS. My class variable is race. I got a low p-value. What exactly does that mean?
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13 views

Significant interactions force main effects to be insignificant and plus change their sign--how to interpret? [duplicate]

I've read through many similar posts regarding significant interaction wiping out the significance of main effects, but since there were no questions regarding changing signs I decided to post another ...
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6 views

How to interpret the results of an analysis dbRDA?

I want to analyze the effect of landscape variables (size of the fragments, isolation and time of fragmentation) on the coverage value of a species matrix. For this, I used a distance based redundancy ...
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1answer
25 views

Interpreting a longitudinal generalized estimating equations beta cofficients

I've been struggling with wrapping my head around the GEE beta coefficients and I don't think I fully get it. There are other questions on CrossValidated that ask about GEE in the binary context ...
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1answer
30 views

Log-level model: variable in % -> what does that mean?

I have big trouble interpreting the following: I run a Fixed Effects model for (extract): Ln(Aeronautical cost) = share International Pax in % + share non-aeronautical revenue in % + share ...
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1answer
34 views

interpretation of coefficients from linear regressions with log dependent variable

I have a seemingly trivial yet troublesome question. Let's consider the following model: $$\ln(y_i)=\alpha + \beta D_i + \epsilon_i$$ where $D_i$ is a binary variable that indicates whether ...
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9 views

Interpreting standardised major axis (SMA) outputs

This is my first attempt at analysing a SMA output, seems simple enough , although I am afraid I may be reading it incorrectly. This function (sma(FinalBiomass~Diameter*Treatment)) is testing for a ...
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13 views

Interpretation of year interaction terms

I am currently specifying a multinomial logit model estimating labour market transition probabilities using quarterly survey data. I have two specific explanatory covariates that I am particularly ...
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26 views

Interpreting Regressions with (growth) rates as dependent variable

I have several regressions and I care about the interpretation of the coefficient(s) (as marginal effects or very small changes). Y is a variable which is a ratio, e.g. a growth rate or a share (not ...
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2answers
74 views

Does each eigenvalue in PCA correspond to one particular original variable?

I have a matrix of let's say 120 variables and 50 subjects (rows). Before computing correlation between the 120 variables, I want to perform principal copmonent analysis (PCA) on this matrix. I will ...
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1answer
42 views

Interpretation of quasibinomial glht (Tukey) results

I'm analysing chick survival between 3 different years using a glm with quasibinomial error structure. Hence, my response variable is a cbind of fledged chicks and dead chicks, and one of my ...
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1answer
49 views

Interpreting % Var explained in Random Forest output

I've run a Random Forest in R using randomForest package. The fitted forest I've called: fit.rf. All I want to know is: When I type 'fit.rf' the output shows '% var explained' Is the % Var ...
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1answer
32 views

How do I interpret interaction effects in a log-log regression model?

I have the following model: $\log(y)=\beta_0 + \beta_1 x_1 + \beta_2 \log(x_2) + \beta_3 x_1 \log(x_2) $ In interpreting the % change of $y$ that corresponds with a 1% increase in $x_2$ at a ...
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15 views

Are there any circumstances under which a confidence interval can be interpreted as a likelihood interval? What are they?

I read the answers provided to the question "are all values in a 95% confidence interval equally likely?". These answers raise questions for me regarding interpretation. I have read that under ...
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1answer
20 views

Backtransform coefficients of a Gamma-log GLMM

I am analysing data from an exclosure experiment, this means for several years, goats were kept outside a fence and inside the fence, plants could grow without being grazed. Outside the fence, grazing ...
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26 views

Interpretation of SPSS output mixed model

I have an spss output, whereby I included the variable education in the fixed as well as random part of the SPSS mixed model syntax. A multilevel model is estimated whereby Level 2 represents ...
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16 views

Interpretation of cross validation results when comparing models

I'm trying to solve a bio-medical image segmentation problem using a binary classifier and then a spatial smoothing (assuming continuous regions). I have: Training set of 10 3D scans, a total of ~30 ...
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51 views

How to interpret caret's variable importance and feature selection plots?

I am having some problems understanding the variable importance and feature selection graphs from ...
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1answer
38 views

Interpretation of log(1 + x) transformed predictor

Interpretation of log transformed predictor neatly explains how to interpret a log transformed predictor in OLS. Does the interpretation change if there are 0s in ...
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2answers
82 views

How do I interpret and report the output of a logistic regression in R on data that are all binary (0,1)?

My minimum adequate model is shown below. My independent variables (e.g. One, Five) represent habitat categories for which species have either been designated to (i.e. the assessment found that they ...
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1answer
17 views

transitive property in statistical comparisons

I want to know if the exposure to a given dose of a toxic chemical alters the concentration of a given substance in blood in my animals. I make this super general, bear with me, because I think this ...
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0answers
17 views

% of baseline variation explained by did estimator

I am running regressions of the type: $y_{it}=\alpha + \delta T_{it} + \gamma X_{it}+ \lambda_{t} + \epsilon_{it}$ where $T_{it}=1$ for some observations for $t>\bar{t}$ and $T_{it}=0$ ...
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1answer
43 views

Interpretation of coefficient in log-linear model with share predictor

There are several questions on the interpretation of coefficients in log-linear models such as Interpreting regression coefficients of log(y+1) transformed responses Log linear model interpretation - ...
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50 views

How to interpret conditional odds ratios from a three-way contingency table?

I am trying to understand how to correctly interpret the estimated conditional odds ratios from a loglinear model on a three-way contingency table. This is an example from Agresti 2013 (p. 346, ...
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25 views

Interpretation of coefficients from GLM (family Poisson) regression

I am running a GLM regression from the Poisson family. My dependent variable is the number of train accidents per month, and I define as offset variable the total number of train routes for that ...
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25 views

Promotion analysis with regression, negative coefficients

I used multiple linear regression to model promotion effects on sales on sample retail store, but some coefficients becomes negative. As a business interpretation, should I consider these promotions ...
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23 views

How to understand PCA output in R? [duplicate]

I have problem on understanding the PCA output. I found two ways of doing PCA: 1) pca <- prcomp(inputdata); 2) do it myself: ...
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1answer
18 views

How to interpret simple effect of a variable interacted with several others?

I am sure this has been asked before (similar here but no answer). But I have not found an answer yet. To give you a short frame: I am researching firm level data and I am ivestigating several ...
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12 views

coefficients in cumulative link models

I used ordinal package to build a cumulative link model: require(ordinal,quietly=TRUE) fm1 <- clm(base ~ . , data = df_reg) summary(fm1) df_reg is a dataset ...
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22 views

How to interpret the output of the anova command in R? [duplicate]

I used the anova function in R to get an ANOVA table for my model. ...
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1answer
31 views

Log linear model interpretation - % Contributions?

I know that for log-lin models the interpretation for the coefficiente is this one, that is: Coefficientsâ‹…100 have a semi-elasticity interpretation: for a 1 unit change in x, you get b*100% change in ...
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1answer
76 views

Interpretation of Bayesian vs Frequentist statement

Although I am completely new to Bayesian Analysis I struggle sometimes when trying to investigate some intersections between Bayesian and Frequentist analysis. I would like to discuss the different ...
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1answer
31 views

Interpreting multiple polynomial regression coefficients

I read a couple post on interpreting polynomial coefficients here in cross validate however none of them touch on how to interpret multiple polynomial regression coefficients. Perhaps its the same but ...
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2answers
51 views

How to interpret a two-dimensional contingency table?

I am trying to understand how to interpret log-linear models for contingency tables, fitted by way of Poisson GLMs. Consider this example from CAR (Fox and Weisberg, 2011, p. 252). ...
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1answer
36 views

Independent variable as a percent in a binary logistic regression

I understand the basics of binary logistic regression when the independent variable is a dichotomous variable. However, I am working with a dataset that has the dependent as a dichotomous variable ...
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1answer
60 views

R: interaction in model output

Let's say you're trying to fit a model to a dataset that includes categorical variables, group (A or B) and treatment (1, 2, 3 or 4). In R, your model formula would be DV ~ group * treatment (DV ...
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19 views

Interpretation of KPSS-Test results

I'm analyzing the monthly german industrial production growth rate which should be a stationary time series. I use different samples and want to compare predictions of different inidcators. I first ...
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149 views

Standardized VS centered variables

I have found many useful posts about standardized independent variables and centered independent variables on stats.exchange.com, but I am still a bit confused. I am asking you an evaluation of what ...
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1answer
30 views

How can I analyze / compare point-of-sales data between stores with different product offerings?

Let's say I have two stores, A and B, and let's say I have two products in the same department: product 1 and product 2. Let store B have product 2 which store A doesn't have, both stores have product ...
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0answers
25 views

Issue in Interpreting SPSS output of GLM repeated measures

I have a data set with repeated measures for each individual. That is there a re two groups, treatment and control. And each individual is measured at 3 time points. But there are missing values. That ...
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2answers
24 views

ANCOVA Supressor effect?

I'm having a wierd kind of effect I don't fully understand when running an ANCOVA analysis. To keep it simple I have a variable X and a variable Y, these variables are significantly correlated to ...
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109 views

Interpreting regression coefficient - what units are fractions?

I am regressing a growth measure (in fraction form, between 0 and 1) on another fraction that lies between 0 and 1 (let's call the variable ``share"). The regression is performed using OLS. What is ...
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11 views

Interpretation of deviation coded data in mixed effects models

ran a model with reaction time as my DV and PWI Condition as one of the fixed factors. I used contr.sum for all fixed factors. I ran the following model to look for differences in reaction time ...
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19 views

Finding a reaction norm in R using logistic regression with binomial errors

I am trying to calculate 'reaction norms' for a fish species. This is essentially the length at which the probability that a fish become mature equals 50% for a particular age class. I know I have to ...
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0answers
19 views

What does the following ADF test in R signify?

While checking for stationarity of differences (first difference) data using ADF test in R, I get that the test statistic is significant for all the deterministic regressors - "none", "drift", ...
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1answer
22 views

How to compare utilization rates?

I have the utilization rates of several machines for each week over a year. These differ per week because of the occurrence of machine failures and changes of orders. Meaning that one week a machine ...
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1answer
38 views

Interaction terms in cross-sectional regression

I have a question regarding the use of interaction terms in a cross-sectional regression model. Currently I am working on a study for which I have a sample consisting of roughly 500 observations, ...
2
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2answers
190 views

How will changing the units of explanatory variables affect a regression model?

Let's say I am predicting weight from height (cm) and age (years). Then I decided to convert height into meters and age into months. The interpretation of the coefficients out of the regression might ...
4
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1answer
53 views

pvalues of glm coefficients and heavy tailed distributed residuals

I've seen this post but I have still some additional questions. I have a ordinary linear regression model with more then 300 predictors (which represents different conditions). I want to know which ...
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1answer
45 views

Interpretation of the magnitude of the effect of interaction terms

I have a model with interaction terms: $Y = a + b X_1 + c X_2 + d Z + f X_1 Z + g X_2 Z + error$, where $X_1$ and $X_2$ are (0,1) indicator variables and $Z$ is a continuous variable (with a ...