Questions tagged [group-differences]
Group differences broadly refer to statistics which quantify the differences between two or more subpopulations.
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Comparing factor scores between groups
I have participants who have taken an intervention and are being measured at two different time-points. It is expected that the intervention will improve their knowledge, attitude, confidence etc. and ...
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Question about variance explained and group differences
A heritability statistic, as I understand it, describes the percent of variation in a trait that is attributable to genetic variation, with the rest attributable to environmental variation.
I've heard ...
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difference in differences
I'm looking to work out the difference in effect (time to surgery) between two patient populations (exposed and unexposed groups) and compare between two countries (i.e. difference in differences).
i ...
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Multiple group analysis in canonical correlation analysis
Canonical correlation analysis estimates the relationship between two canonical sets of variables. However, I am interested in using a technique to compare these CCA results across groups (something ...
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Which test to use for 13 groups?
I am conducting a preliminary study on a medical sign.
Without going into details, I have 13 types of dermatological diseases (variable x) presenting as skin lesions. In each group there are between ...
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Appropriate statistical test to determine if uplift between control group and multiple test groups is significant (pretest/posttest evaluation)
I'm trying to evaluate whether the difference in uplift seen in below table between the test groups and the control group is statistically significant. I'm unsure about the appropriate statistical ...
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Statistical test for survey data
I am a water quality scientist who is using water quality data from my region to determine if certain demographics are more likely to have poorer water quality (for example, by race).
The data was ...
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Relating factors based on conclusions on 2 distinct groups?
I determine that Team A achieves higher customer satisfaction scores than Team B with wilcoxn rank sum test. A customer satisfaction score is calculated from different sized groups of customers, and ...
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When to use Spearman correlation and when to use Wilcoxon Rank sum test?
I have collected data on 1680 test scores and 1680 participation rates from 7 different courses and 4 different semesters using information from 60 students.
I am confused of whether to use a ...
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Can I move on to the next level (test) of invariance when my fit gets better?
I am running a group invariance test.
The data consists of data from students from grades 5 and 6 for one school (School A)
and only from grade 5 in another school (School B).
I have already run group ...
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Comparing ranks from differently sized sets across conditions
I performed a treatment-control experiment, with $r$ repeats per group. Each repeat $i$ consists of a set of $n_i$ observations. Each observation $j$ consist of a rank $x_{ij}$ and a class indicator $...
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How much does model fit affect the analysis of an invariance test?
I am currently running a group invariance test with R, lavaan.
My total sample is 794. The results came out as the attached photo.
I understand that the chi-sq, CFI, and RMSEA all indicate that full
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Normalised Differences
I have a dataset where my main variable is smoking. I have three definitions of smoking based on different questions and there are overlaps. By the first definition I have 100 people who are smokers, ...
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test for comparing the size of the treatment effect?
I am analyzing experimental data and would like to know the most appropriate approach.
For sake of simplicity, the setup can be described as follows: the data is for students who are either high-...
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Improve estimation of effect-size (difference between two distributions) by using LDA distance to decision boundary
Before getting to the point, I will provide some context:
I have a dataset that includes $176$ quantitative neuroimaging markers ($m_i$ for $i=1,...,176$) and several categorical variables ...
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How to compute CI for reference group in multiple group SEM?
I am comparing several age groups on one latent factor with SEM in lavaan. The model shows strict invariance and i want to compare the latent means of the different age groups. To do so, i also want ...
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When the group interaction in multiple regression is not significant, shall we include the group variable in the following regression models?
I want to explore the relationship between biological markers and cognition in healthy controls and patients. In order to determine if the relationship varies between groups, I included the ...
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Finding subgroups in population, using individual effects of hierarchical model
I want to know how to look for effects both at a population level, and at an individual level in an experiment. I was wondering if I can do this with hierarchical Bayesian models as follows.
In a ...
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How to compare more than two groups of continuous, not-normally distributed values?
I'm currently analyzing the age variable in a dataset of all italian phyisicians (~470,000 obs) and I'm trying to check if age is significantly different between three groups defined by another ...
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Compare latent trajectories of two groups based on same model using SEM
I fit latent growth models using lavaan's growth() function in R. It looks like this:
...
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Difference between two paired non-normal groups
My Data: Respondents were asked to evaluate the quality of two products on a scale of 0-10. There were 12 criteria that constituted the grading scheme, and I would like to analyze the scores overall (...
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Compare and find p-value between two t-tests
I am running a statistical test to determine if females are more influenced by the framing effect. I designed a survey with three overall questions, each with a "positive frame" and a "...
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Sample size calculation in two different population for administration of a questionnaire
I need some help calculating a sample size.
I have two groups of people to whom I need to fill out a questionnaire. Group A consists of 45,000 people and group B consists of 3,000 people.
How do I ...
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Variance low and ceiling effect - split by median`?
I heard that a sufficient amount of variance/heterogenity is needed in order to get reasonable results for a correlation test.
Why is that and what solutions exist when variance is too low?
Is ...
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Different results of t test and biserial correlation?
I was wondering whether it is possible that a t test and a point biserial correlation can give different results (t-test shows groups differ significantly, correlation implies that variable does not ...
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Use t-statistics to measure between group differences
I have read a paper (https://doi.org/10.1038/s41591-023-02296-6)
in this paper, fig 5, the authors point out:
between-group differences (disease versus health, t-statistics,
two-sided) in body (n = ...
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How to compare habitat selection coeficients between groups?
For my thesis I am analysis habitat use of animals. I want to compare habitat selection coeficients between groups, for instance between males and females or between different places. But I do not ...
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Decomposing difference in outcomes between two groups
I have a simple problem, but haven't found a solution yet.
Let $Y_{i}=\sum_{a} X^{a}_{i}*\omega^{a}_{i}$, where $Y$ is something I calculate, and everything else is observed.
$\sum_{a} X^{a}_{i}=1$, ...
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Is it correct to estimate covariance matrix of null distribution of related random variables using independent groups as data points?
I will use an example of an antidepressant drug trial as an example to illustrate my question - hope this helps as I, too, am confused.
Suppose a study is testing the effects of some drug on people ...
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Train Test leakage
Imagine the following dataset. 1 --> Person buys this product sometimes 0 --> Person never buys this product:
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Compare R2 and Pearson correlation in different models
I have a data set with two variables (var1 and var2) and two binary variables Sex (1,2) and Time (1,2). Therefore, I have four groups.
I have calculated pearson correlations and R2 for the four groups....
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Score for over/under representations of a variable in sub-group
I have a corpus of book publications split into different clusters. I have information about the nationality of the authors (variable A) and the nationality of the publishing company (variable B).
In ...
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Understanding the affect of sample composition changes on mean over time
I am working on a problem that is similar to the following.
Suppose I am interested in understanding what is causing the mean price of apples to change from month to month.
My dataset has a similar ...
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Compare two groups with differnt treatments and different populations
I will simplify my research question. I have 40 patients (group 1) with assessed a variable v1 (e.g. their blood preassure) at timepoint 0 ( v1(t0) ). After treatment (treatment 1 at timepoint 1) I ...
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Discussion regarding a non-standard method to compare multiple groups of algorithms on different tests
TLDR: I am trying to compare groups of machine learning algorithms across a set of datasets. I understand the usual methodological procedure to compare the algorithms but I believe there is a ...
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Comparing microRNA expression at different tumour stages and identifying trends in miRNA expression
I'm currently working on a university project using publicly available data. I'm collecting genome data on cancer patients at different pathological stages (Stage I, II, III and IV).
I'm aiming to ...
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Distribution and difference between two categories in two corpora, and comparison
Building on this question:
I'd like to compute the difference between the presence of a 2 level factor in 2 datasets, and see whether this is significant.
For instance, let's say I want to find 2 ...
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How to compare one continuous variable between two groups when there are gender-specific reference values for the variable?
I want to compare two groups of patients - hospitalized and non-hospitalized - by one laboratory parameter value. There are male and female patients in both groups. But, for this laboratory parameter, ...
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Difference between the ratio of test statistics between two or more groups
Assume we have 5 or more groups consisting of sales and margin observations, and that we want to find if there is a significant difference in two test statistics, the mean sales $S$ and the mean ...
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How to compare the socioeconomic status between two populations after applying multiple correspondence analysis?
I have two datasets of two populations (before and after)
with the task to create socioeconomic quintiles. Through many variables such as household assets and household quality, I used MCA (R language)...
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Comparing AUC-PR between groups with different baselines
So I know that the area under the precision-recall curve is often a more useful metric than AUROC when dealing with highly imbalanced datasets. However, while AUROC can easily be used to compare ...
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Independent "measurements" analyses - check if factors under investigation are relevant or not
Thanks to my poor statistical knowledge, I need help to understand if exists a way to analyze the data and achieve the result I have in my mind. I must admit that the intentions are a bit broad.
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Calculating difference in means confidence interval using only standard errors, sample sizes, and means
I use a complicated survey-corrected estimator to calculate a mean and standard error for one year and then redo the process to calculate a mean & se for another year (using IEA education data ...
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Non-significant multi-group analysis - which model should I interpret?
I ran a multiple group (three groups - each group is a different country) analysis to explore possible cultural differences in my model.
The results suggest that the differences are not significant - ...
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GEE how use two different working matrices?
With longitudinal repeated measures of the same person, is it possible to have two different working matrices depending on a the value of a within-person binary predictor variable?
Suppose there are ...
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Does measurement non-invariance between groups matter in difference-in-difference designs?
Claim:
If a measure has a difference in measurement invariance (i.e. the measures are non-invariant) between two groups (say treatment and control), which is constant across time, then a difference-...
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Can you help me determine if these two groups are statistically different?
I have two groups, A & B. Let's say A are the users who wrote a review for place A, and B for place B.
For each user $u$ I have recorded his total number of reviews $r_u$. Since we're talking ...
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Test for difference of individual relative proportion and group proportion
I work at a cancer registry and am currently stuck with the following problem: I analyze the data quality of reporting institutions and individual doctors reporting from within that institution. I ...
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Can I increase number of observations in a group to compensate an increased variability, and account for it in weights in a regression?
I don't really know the norm to justify the use of weights in regression, but I was wondering if I could use them to account for some confound variable that I know about.
Basically I am asking ...
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Comparing multiple sample proportions between two treatments
thanks for reading this. I'll try and be as clear as I can but I am very new to this sort of stuff.
DATA: So I have two treatments with multiple replicates and replicates are paired between the ...
