Tagged Questions

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

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4
votes
1answer
39 views

Using predicted probabilities as regressors

I am working on a project where I investigate growth in wages due to migration. I correct for the endogeneity in the decision to migrate (only those that are most likely to gain from migration will ...
5
votes
1answer
76 views

Meaningful inference about data structure based on components with low variance in PCA

A lot of microbiome (microbial ecology) papers that I have come across use either principal component analysis (PCA) or principal coordinate analysis (PCoA) to make conclusions about the data. A lot ...
1
vote
1answer
21 views

Interpretation of significant interaction

I look for an intuitive understanding of interaction effect in ANOVA or regression. Let's keep things simple as the following. Suppose we have a standard 2 x 2 factorial design, where each factor ...
0
votes
1answer
26 views

prediction from panel regression

My question is simple (code and data at the bottom): suppose I run panel data regression (fixed effects using first differences) and I want use the estimate to generate prediction for a given data (a ...
1
vote
0answers
32 views

Tweedie P Value Interpretation

From Wikipedia (http://en.wikipedia.org/wiki/Tweedie_distribution) we know that The Tweedie distributions include a number of familiar distributions as well as some unusual ones, each being ...
0
votes
1answer
26 views

Compare means of two (contentwise) different variables

I have a question about comparing the means of two variables that have a different meaning but a (possibly) similar ways of measuring them. To give an example: Let's say I am conducting a study in ...
2
votes
1answer
69 views

Wrong Intepretation of Kruskal Wallis Test in R

I have some data (called egecNonmated) in R and I am trying to show that the distributions of a variable (MatchScore) are identical across three different Categories (Cat). I am using a box plot to ...
3
votes
1answer
85 views

Interpretation of interaction term

I have a model: $$ \ln({\rm earnings}) = a+b_1{\rm female}+b_2{\rm white}+b_3{\rm female}\times{\rm white} $$ ${\rm female}$ and ${\rm white}$ are dummy variables. I have interpreted $b_1$ and $b_2$: ...
1
vote
0answers
33 views

Interpreting output from cvFit(), understanding cross-validation in classification tree model

I am trying to understand how to interpret the output for cvFit(). The data is from UCI's ML repository. This is my model ...
3
votes
1answer
69 views

Interpreting results of chi-squared

Situation: A/B test of a single website change on a landing page. Alternating visitors to the landing page are shown a variation. The goal is to convert more visitors into customers. With data that ...
0
votes
1answer
44 views

estimating LMM with r

Suppose I have a model $$\begin{bmatrix}y(1)\\y(2)\end{bmatrix} = \begin{bmatrix}\mu \\ \mu \end{bmatrix} + \begin{bmatrix}\Lambda \\ \Lambda\end{bmatrix} + \begin{bmatrix}\varepsilon(1)/\rho_1\\ ...
1
vote
0answers
52 views

PSM, Diff-in-Diff and Neg-logged income variable? How to interpret estimates?

I am estimating a difference-in-difference based on propensity score matching. The "treatment"-variable defines whether a household registered for a public insurance which was only active for two ...
1
vote
0answers
61 views

interpreting y axis of a partial dependence plots

I have read through other topics on partial dependence plots and most of them are on how you actually plot them with different packages, not how you can accurately interpret them, So: I have been ...
0
votes
0answers
25 views

Statistic confidence interval

I have this statement: If a 95% confidence interval for the mean was computed as (25,50), then if several more samples were taken with the same sample size, then 95% of them would have a ...
1
vote
1answer
71 views

Interpreting a linear mixed effect model's interaction term

I am a biologist and am attempting to analyze the effects of time and location on depth. I was told I needed to use a mixed effects model to account for the random variables of Individual and tracking ...
1
vote
1answer
39 views

Best practice for visualizing a lift from zero?

Let's say you have two columns of data. Column A represents a value you had last month, and column B represents a value you have this month. If you want the percent change between the two, you math ...
2
votes
1answer
45 views

Interpretation of logged regression

I have run a linear regression with the following equation (in r): lm(formula = logTotal ~ Continent + logArea + Method + Servs) where ...
0
votes
0answers
41 views

Variance in significance with interaction term

I try to estimate the effects of NatRent (Natural resource rents in % of GDP) on GDP growth per capita (in %). When I include a Rule of Law (a measure for institutional quality) the coefficient of ...
2
votes
1answer
58 views

Interpretation of betas when there are multiple categorical variables

I understand the concept that $\hat\beta_0$ is the mean for when the categorical variable is equal to 0 (or is the reference group), giving the end interpretation that the regression coefficient is ...
1
vote
1answer
46 views

Spearman's rho for nominal / metrical data

Can Spearman's rho be used to calculate correlations between nominal (i.e., locations such as 1 = City1, 2 = City2, 3 = City3) and metrical data (i.e., revenue generated in US dollars)? I also heard ...
4
votes
1answer
82 views

How to interpret autocorrelation plot in MCMC

I am getting familiar with Bayesian statistics by reading the book Doing Bayesian Data Analysis, by John K. Kruschke also known as the "puppy book". In chapter 9, hierarchical models are introduced ...
1
vote
2answers
78 views

How to interpret PCA for data reduction?

I have 19 currency pairs like USD.AUD, USD.CAD, etc. Also 82 cross currency pairs like ...
1
vote
2answers
61 views

Controlling for age in multiple regression

I am a little stuck on what how to implement and interpret a multiple regression while controlling for age. I am interested in seeing if there is a positive relationship between depression and use ...
0
votes
0answers
30 views

Confusion about features selection for inference analysis with lm/glm

I need a bit of tutoring about grasping the true meaning of linear regression analysis. I'd like some help in understanding well the relationships between predictors and and the meaning of adding and ...
3
votes
1answer
79 views

Multilevel logistic regression with a random slope(s)

I would like to specify a two-level logistic regression model with random intercept and random slope. Dependent variable: hospitalization (1) or no-hospitalization (0). Independent variables: age, ...
7
votes
3answers
156 views

How can I interpret a plot of trimming percentage vs. trimmed mean?

For part of a homework question, I was asked to calculate the trimmed mean for a dataset by deleting the smallest and largest observation, and to interpret the result. The trimmed mean was lower than ...
1
vote
2answers
51 views

How to interpret a negative correlation of random effects in a mixed-effects model (in R)?

I've just gotten stuck in interpreting the output for a linear mixed effects model. My model includes Week as a time predictor, and scores on a depression scale as outcome. I have not worked with R ...
0
votes
0answers
14 views

mixed within-between ANOVA. I have a significant interaction but no significant main effect

I am currently trying to interpret the output of my mixed within-between ANOVA. I have 2 groups (experimental and control) and 2 time points (pre and post intervention).The dependent variable is a ...
0
votes
2answers
33 views

4-way Repeated Measures ANOVA

exchangers! I am struggling with my data analysis for an article I'm writing. I have to following experimental set-up. Instruction (A/B) Group (Alcohol Dependent / healthy Control) - between ...
1
vote
1answer
141 views

How to interpret ACF and PACF plots

I just want to check that I am interpreting the ACF and PACF plots correctly: The data corresponds to the errors generated between the actual data points and the estimates generated using an ...
1
vote
0answers
19 views

Why normalized feature weights for linear regression are bad feature importance predictors

I am trying to interpret a linear regression model. I assumed using absolute value of feature weight coefficients as indicators of influence of input variable onto output variable. However, it seems ...
0
votes
0answers
52 views

How are statistics on scientific papers inferred?

Referring to this question: How should be statistics on scientific papers read?, a kind user explained us how to read the following statement from the original research paper:. Increasing ...
3
votes
1answer
79 views

How should be statistics on scientific papers read?

Let's take this research published on Plos ONE Increasing carbohydrate intake was associated with increasing stroke risk (HR = 2.01, 95%CI = 1.04–3.86 highest vs. lowest quintile; p for trend ...
0
votes
0answers
31 views

How to interpret 3 main effects when an interaction exists for only two of the variables?

I've been searching for interpretation guidance regarding the below problem, but all the resources I've seen have been fully crossed (i.e., all variables included in the interaction term). Below is a ...
3
votes
1answer
67 views

Interpretation of odds in logistic regression

I have been reading the odds tutorial on UCLA's stats page. And I am trying to figure out if my interpretation of the results below is correct. Based upon looking at the data the results seem to hold ...
-2
votes
1answer
43 views

Graph Interpretation

I would like to ask what could be the most possible interpretation of these two graphs attached. One of them depicts conditional probabilty p(Y|X) whereas the second one shows Y regressed on X. I ...
3
votes
0answers
39 views

Interpretation of log transformed predictor in negative binomial regression

I mainly want to make sure that I'm making the correct interpretation here. I built a negative binomial regression model predicting a count variable. There was evidence of overdispersion or I would ...
0
votes
0answers
4 views

how do i interpret the result for optdesign and the theory behind? [closed]

I am trying to write a project and I am using the package of DoseFinding. I want to figure out the output from the optDesign and interpret it. And what is the theory of TD. I tried to use ?optDesign ...
1
vote
1answer
41 views

How should I interpret a factor that is significant both (1) in linear form in interaction with another factor and (2) in its quadratic form?

Our study aims to identify and understand how several ecological factors relate to parasite abundance in a colonial animal. However, we are uncertain on how to interpret a factor (density) that is ...
1
vote
0answers
81 views

Interpretation of clogit coefficients (Survival package in R)

Still very very new to R! I've run a conjoint (choice) experiment that uses the function clogit. Output as follows: (this model has been obtained through stepwise methods) ...
4
votes
2answers
128 views

Interpretation of multiple logistic regression with interactions in R

I am trying to look at whether 2 variables (one dichotomous categorical and one continuous) predict the occurrence of a dichotomous categorical dependent variable. ...
3
votes
1answer
169 views

How to interpret non-significant interaction term in linear regression?

I have difficulties interpreting an interaction term in a linear regression with regards to my hypothesis. Consider this basic example: H0: Better school grades lead to higher income and this ...
2
votes
4answers
758 views

How do you interpret a significant but weak correlation?

I have carried out a number of Pearson Chi Square tests on the relationship between tail lesions and abscessation in pigs. I have found a significant (p = 0.005) but weak (Cramers V = 0.288) ...
0
votes
1answer
24 views

Is there a statistical differing interpretation between match and fit?

I've seen the terms matching/match and fitting/fit used almost interchangeably when discussing models goodness of fit, observed vs simulated data matching, etc. Is there a difference in ...
0
votes
0answers
11 views

Describing the association between dependent and independent variables [duplicate]

I’m somewhat confused about the (wording of the) interpretation the coefficient (b1) of a classic OLS regression: Y = b0 + b1*X + e In the literature, the two interpretations: b1 reflects the ...
1
vote
1answer
110 views

Can I still interpret a Q-Q plot that uses discrete/rounded data?

I have a data set with only discrete/rounded values in it. As a result, when I produce a Q-Q plot a "stair-case" pattern appears. Can I still interpret this just like a normal Q-Q plot even though it ...
0
votes
0answers
56 views

GEE in SPSS: the case of ever-decreasing QICc values

I've been using GEEs in SPSS 22 to analyze my dissertation data and have discovered an interesting problem: when trying to figure out which subset of model factors have the lowest QICc, and therefore ...
0
votes
0answers
30 views

Interpreting results from a mixed model with interactions

I need your help interpreting my model's results. To make story short, I have a continuous dependent variable $Y$, and two factors $A$ and $B$, each with $2$ levels $(A_1, A_2, B_1, B_2)$. My main ...
0
votes
2answers
29 views

Help in regression interpretation, including interaction terms

I m doing a quantitative analysis for my dissertation and I m having issues with the interpretation of my results (I have little knowledge of SPSS). I m doing a panel data analysis with multiple ...
1
vote
0answers
37 views

Am I using Goodman-Kruskal gamma or Somers D or Kendall tau correctly and what do they mean?

I am seemingly blindly following this publication that has done work very similar to what I need to accomplish (page 18-21). My analysis is a multinomial logistic regression where I have 3 possible ...