All Questions
1,501 questions with no upvoted or accepted answers
2
votes
0
answers
342
views
Combining Fixed Effects and Random Effects Confidence Intervals, Is this Possible?
I estimated a random slope,random intercept model and have estimates of the fixed-effects $\beta_i$ and the random effects $b_i$. I also have their associated standard errors $SE_{\beta_i}$ and $SE_{...
- 619
2
votes
0
answers
681
views
Parametric versus nonparametric AUC from ROC curve
SPSS offers two ways to estimate Area Under the Curve (AUC) and its standard error, that is nonparametricly using trapezoidal rule or parametrically using binegative exponential distribution. I have ...
- 905
2
votes
1
answer
45
views
How to relate 2 sets of classifications (types of runners & motivations)
I am currently writing a proposal and am confused regarding which statistical method I should use. I aim to examine the motivation of runners in participating a charity marathon. It will use runners ...
- 21
2
votes
1
answer
221
views
what's the difference between weighting and transforming?
In regression analysis, what's the difference between weighting and transforming when it comes to spreading residuals? For example, we need to weight the model $y=ax+b$ by $1/x$, isn't it just ...
- 757
2
votes
0
answers
525
views
Transformation and/or Winsorizing?
I want to compare two group of 24 and 28 people with t-test on type of activity (5 different's types of activity and a total), later one the same value will be use in regression logistic.
If you ...
- 41
2
votes
0
answers
316
views
Questions about mixed model design with repeated measures/nesting/incomplete design
I have data from a incomplete factorial experiment with repeated measures and potential nesting and am trying to figure out 1) the right way to design the mixed model to analyze the data, and 2) how ...
- 424
2
votes
0
answers
125
views
Centering makes model insignificant
To determine whether multiple independent variables predict a dependent variable, I'm using a hierarchical model of three levels (first level: only control variables, second: control and independent ...
- 101
2
votes
0
answers
637
views
Interpretation of continuous by continuous interaction in binary regression model
I'm performing binary logistic regression in SPSS; y is dichotomous variable; and both Xs are continuous variables.
I performed three models and I have troubles interpreting model with both ...
- 21
2
votes
2
answers
334
views
Statistical relationship with both dependent and independent variables percentages that sum to 1
I'm trying to see if there is any relationship between the market share of a company (dependent variable) and the "tweet share" of this company (independent variable). The tweet share of a company is ...
- 21
2
votes
0
answers
95
views
comparing survey responses
I have requested 30 participants to answer the same question about 100 images: "How easy is it for you to recognize this image?" on a scale from 0 to 100, where 0 is easy and 100 is difficult.
I want ...
- 21
2
votes
0
answers
778
views
Can Cochran's Q test take a 3 level nominal variable as the response (instead of 2)?
I conducted a study using within-subjects (repeated measure) design for collecting nominal data. I have been reading a lot closet I get for a suitable test is Cochran's Q test since I have repeated ...
- 23
2
votes
0
answers
5k
views
How to incorporate weight into linear regression in SPSS
I would like to know the proper procedure to execute weighted linear regression analysis. I have come across different tutorials about weighing in SPSS, but can't distinguish which is appropriate. ...
- 1,197
2
votes
0
answers
56
views
Clarifying which ANOVA to use
In my study, all participants underwent a decision task, followed by a training task, followed by a decision task. ALL participants had a response delay on ONE of the decision tasks. This was ...
2
votes
0
answers
232
views
If all components of a hierarchical model have not converged, can we say that any parameters have truly converged?
I'm working with a hierarchical regression model of the following form similar to that presented in Peter D. Hoff's book, A First Course in Bayesian Statistical Methods:
$\boldsymbol{Y}_j \sim \text{...
- 619
2
votes
0
answers
544
views
Matching with multilevel data
I've got a dataset where a treatment $W$ has been applied to units $i$ within clusters $c$. $W$ is constant within each cluster. As a component of an algoritm that I'm implementing (which was ...
- 13.7k
2
votes
0
answers
182
views
nnet vs glmer for multilevel logit
I have data where I'm interested in the effect of treatment on individual decisions: Options 1, 2, & 3. Individuals made multiple decisions (level 1) in groups (level 2).
I want to know the ...
- 21
2
votes
1
answer
34
views
How to analyse differences in groups over time?
I have a data set which looks at the effect of diet on 3 different vitamin concentrations (eg. vitamin d, c, iron). There are two measurements for each vitamin - one at the start of the study and one ...
2
votes
0
answers
630
views
In a linear mixed model what does the F value represent?
I am examining the output of my linear mixed model in SPSS and need to decide how to report my findings. I was considering just reporting the p-values. However, my supervisor wants me to provide more ...
- 315
2
votes
2
answers
90
views
Detecting change in % responding to a question over time periods
A study has been asking the same ratings questions repeatedly year over year. Currently, the study is using a Column Means test in IBM SPSS Survey Reporter to compare the number of people responding ...
- 21
2
votes
0
answers
4k
views
Multilevel analysis: panel data and multiple levels
Suppose we have a historical (panel/longitudinal) dataset on the number of buildings in each sub-region (this is a made-up dataset to explain the concept):
The variable “Year” ranges from 1 to 10 and ...
- 162
2
votes
0
answers
394
views
How to use matching methods with multilevel data?
I am very new to matching and multilevel models, so I hope my question is not too naïve.
I have a time series data set with a binary dependent variable measured at the individual level, a dichotomous ...
- 205
2
votes
0
answers
263
views
Computation of factors after factor analysis
I have run a principal axis factor analysis and I want to form scales for each factor. To be more specific, after having run the FA, I would like to select all items that load in a specific factor and ...
- 163
2
votes
0
answers
1k
views
Back transforming reciprocal transformation for difference between means
Say I have the following datasets which concern normalised masses like this:
Set 1:
3.08,
2.79,
3.62,
2.62,
2.85,
2.45,
2.80,
2.62
Set 2:
3.25,
3.14,
3.30,
3.13,
3.19,
3.17,
3.35,
3.35,
3.82,
3.13
...
- 587
2
votes
0
answers
513
views
Cox survival analysis versus multilevel modeling
I'm debating the wisdom of a couple different approaches.
I am constructing a model that measures whether the amount of a treatment received leads to a person coming back for another treatment or not....
- 604
2
votes
0
answers
595
views
Comparing measurements obtained from >2 devices (Bland-Altman, Tukey mean difference plot)
I would like to compare different measurements in regard to agreement. Quite often this is done using a Bland-Altman plot (also called Tukey mean difference plot) in medical literature.
What I would ...
- 51
2
votes
0
answers
325
views
Correlation with stratified data structure
I have a dataset with two stratas, the first level is called block, which represents the census block. the second level is two predetermined subgroups in each blocks, each subgroup contains several ...
- 237
2
votes
0
answers
581
views
Interpreting interaction between time and time-varying predictor in mixed models
I have measured the DV and predictor at 2 timepoints in a single group, and am using the MIXED procedure in SPSS. I want to see whether change in the DV over time is predicted by change in the ...
2
votes
0
answers
1k
views
Nominal or ordinal?
I've got several variables in a dataset of which I'm not really sure what type of data they are: nominal or ordinal.
Context: the variables are part of a dataset in which each case a student. Of ...
- 121
2
votes
0
answers
347
views
Logistic regression: Absolute values for P
I am stuck with a problem (actually two problems).
I have a dataset of about 150 cases and 30 or so dichotonous (yes/no) parameters. I selected 6 parameters (after literature study and crosstabs) for ...
- 21
2
votes
0
answers
66
views
Why would standardized betas be high (e.g. .66) but non-significant in moderated regression?
Running a moderated regression using PROCESS macro in SPSS (issue replicated by running the same moderation using mean-centered variables in SPSS linear regression command box), I am finding that the ...
2
votes
0
answers
73
views
Using Random Effects As Independent Variables in Other Models?
I was having a discussion with a colleague yesterday about an analysis he was doing with some student achievement data. We got into a discussion of value added models (VAM), which in my understanding ...
- 382
2
votes
0
answers
59
views
Correlating aggregated values between groups
I am currently analysing data from household surveys in 27 Indian villages in 7 states, with about 30 cases in each village (807 in total). The aim is to find relationships between various factors and ...
- 21
2
votes
0
answers
613
views
Polynomial contrast in mixed anova with type III SS
I'm trying to replicate SPSS output in R for a mixed ANOVA with a polynomial contrast to test a linear trend.
I fitted a mixed ANOVA in R (see code below), but I can't figure out how to get the ...
2
votes
0
answers
250
views
Compound Poisson Distributions: When, Why, and How To Split the Problem
I've just stumbled upon the Compound Poisson Distribution (CPD) and it seems to be precisely what I need. For the purposes of this post, let's suppose I have a store that sells many items of ...
- 3,615
2
votes
0
answers
380
views
Multilevel model with repeated data and time fixed effects?
I am using pooled cross sectional survey data to estimate prefernce for redistribution. I have 33 countries for 6 survey rounds covering the periods 2000-2013.
I would like to estimate the effects ...
2
votes
0
answers
243
views
Multiply imputing data, but using just one of the imputed data sets
All,
I have a question about what's practical when it comes to presenting results of multiply imputed data. I'm well-versed on the difference among MCAR/MAR/MNAR and approaches to imputing the data ...
- 221
2
votes
0
answers
94
views
How to analyze data with DV only measured at the group level and moderator measured at the individual level?
This may be a relatively simpleton kind of question to ask, as this forum seems to be rather statistically sophisticated, but I'm rather mixed up right now.
I ran a study that involved individuals ...
- 21
2
votes
0
answers
425
views
Multilevel model for causal inference using observational data
I am trying to follow the lecture notes by Imbens/Wooldridge (http://www.nber.org/WNE/lect_10_diffindiffs.pdf) on difference-in-differences estimation.
In page 4, they discuss the general framework to ...
2
votes
0
answers
282
views
Comparing two curves with peaks
I have a question about analysis method and I would be very grateful for the help!
So, I have two groups: Active and Placebo, each group is measured for 20 different concentrations (from 1 to 20) 6 ...
2
votes
0
answers
24
views
How to share weights of between regression models when you learning them simultaneously?
I have many phenomenons which I want to model them as lasso regression problem.
every phenomenon have it's own distinct features set. but for some phenomenons, the subset of features set are the same(...
- 2,743
2
votes
0
answers
4k
views
Relative weights in regression analysis in SPSS: Matrix-approach vs. factor and regression
I am trying to perfome a relative weight analysis as described by Johnson (2000). I have 13 predictors to a more general indicator.
Initially, I started by: running a principal component analysis ...
- 21
2
votes
0
answers
171
views
Predicting dropout in an ordered process: Cox regression, autoregressive model, multilevel modeling?
I am working on a project in which I collected data about 100 people’s steps in an ordered process. All took at least one step, with some continuing up to a fourth step. Each person either drops out ...
- 658
2
votes
0
answers
898
views
What is a "discriminant function" and how to interpret it?
I want to test a model using discriminant function analysis. My question, as the title states, is very basic: What is a discriminant function? That is, how can I interpret the different discriminant ...
- 390
2
votes
0
answers
147
views
Sample size calculation for multilevel, longitudinal experiment
I'd be grateful for any advice about how to do a sample size calculation for the following design. We are interested in the impact of two variations of an intervention on hospital in-patients' ...
- 121
2
votes
0
answers
65
views
Methods for measuring snowball effects in a "complete" longitudinal dataset
I'm looking for ways to test for "cumulative advantage" effects in a longitudinal dataset (see image)
I guess the data set is principally similar to this: http://www.caldercenter.org/whatis.cfm , but ...
- 21
2
votes
0
answers
2k
views
Understanding repeated covariance types in SPSS?
I am working in SPSS on a repeated measures linear mixed model and I am having a really hard time wrapping my head around how to select a "repeated covariance type". The options are:
Ante-Dependence:...
- 21
2
votes
0
answers
165
views
Questions about G*Power
Since I found an insignificant result, I performed a power calculation in G*Power. But I am not entirely sure if I input the right number in some fields.
My design is a 2(between Ss) x 2(between Ss) ...
- 21
2
votes
0
answers
1k
views
How to: repeated measures anova and Friedman's test with multiple imputations for missing data
I have a study where patients were measured pre-operatively (time_pre), post-operatively (time_post) and long-term follow-up (time_lt). I have 60 subjects.
Data consists of: 5 scale variables (1-100)...
- 161
2
votes
0
answers
754
views
Obtaining the Standard Error of Weighted Data in SPSS
I'm trying to find confidence intervals for the means of various variables in a database using SPSS, and I've run into a spot of trouble.
The data is weighted, because each of the people who was ...
2
votes
0
answers
3k
views
simulate multi-level data for repeated measurements
I am trying to simulate multi-level data for repeated measurements. My design includes just one within subjects factor, no between-subject factor. Consider the case of three treatment conditions with ...
- 741