Questions tagged [group-differences]

Group differences broadly refer to statistics which quantify the differences between two or more subpopulations.

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Difference between two groups of people, each person “is” several characteristics

I have two groups of people, A and B (let's say 15 and 25 people). Each person in each group is characterized by a bucket of features (bucket = 6-18 features). Each feature, during qualitative phase ...
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1answer
254 views

How to quantify the similarity/difference between groups of selected features?

Since I have a imbalanced data to deal with, I randomly down-sample the negative data to reach balanced data for following feature selection and classification. To test feature's robustness to ...
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1answer
40 views

Comparing heteroscedastic groups with sample sizes from 1 to 24… No valid tests?

I'm comparing 1 continuous variable across 36 groups (nurses grouped into 36 hospital units). Several groups have only 1 observation, but most have more, ranging from 1-24 observations per group. ...
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1answer
22 views

Single Group Pre-Post McNemar Table Set Up

I am looking to evaluate if the change in proportion for a group changed pre-to-post intervention. Essentially, is the ~7% increase from pre (~2%) to post (~9%) significant. I am running the McNemar ...
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1answer
177 views

Is it valid to do a mixed ANOVA with one within and one between subjects factor when the between subjects grouping factor has very unequal groups?

I am doing a mixed ANOVA in SPSS where I am currently comparing the duration of certain script handwriting in 2 conditions (1=eyes open and 2=eyes closed) for the same 40 participants in both ...
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11 views

Repeated measures with rotation of subjects within groups

I was wondering if you could help with the interpretation of a potential experimental design. We are testing two versions of a 'group' exam, score (out of 100) being the outcome variable, aggregated ...
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1answer
386 views

Comparing multiple likert items across two groups - is the MANOVA appropriate?

I would love to compare 9 multinomial (4 point likert) and 2 binomial (yes/no) measures across two independent groups but I am not sure what test is most appropriate. Treating the group as the ...
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1answer
350 views

Statistical differences between two hourly patterns

I have 2 groups of subjects, namely: Subjects that are younger than 67 Subjects that are older than 67 Each subject of each group wears a sensor that estimate the metabolic equivalent of tasks (METs)...
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11 views

statistical significance of difference between shares

I am trying to conduct a statistical test of the difference between two shares expressed in percentage points. While I could use a regular t test if the difference was between two means, with shares I ...
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9 views

How to know if there is a difference between two populations or if some feature has influence on a certain response variable Y?

I have a database about claims at auto insurance. I can do the math and get Frequency, Severity, Sinistrality. I need to know if cars with automatic transmission have a higher propensity to accidents ...
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8 views

Obtaining Mean Differences from DESeq2 Output

I have conducted some analyses using DESeq2 and obtained the output. However, instead of interpreting the effect sizes as log2FoldChanges, we would prefer to obtain a model-based mean difference. I ...
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16 views

Testing if number of observations in experimental conditions is statisically different

I was conducting in experiment in which i sold products on a pay-what-you-want basis in 4 different information conditions. Apart from comparing the average willingness to pay across the 4 different ...
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1answer
520 views

Difference between regression between groups vs across all subjects (continuum)?

I'd like to understand this better in terms of drawbacks and suitability. For example, if my data includes investigating differences between 2 patient groups and a control group (3 groups in total), ...
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52 views

Statistical test for dependent data- comparing groups of pairs

I have a question about statistical tests for dependent data. This will sound a bit strange/extremely naive but pls bear with me- here is my problem formulation: I have 500 individuals, and I'm ...
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1answer
37 views

Testing whether the means within group are different from each other (R)

My Y variable is binary and takes the values 0 and 1. The same applies for the independent variable X. I've been able to create the means within the group, here: ...
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0answers
11 views

Test difference of means between subgroups

I have a collection of N samples from which I have computed all pairwise Euclidean distances. The samples can be divided in 3 distinct subgroups. I want to test if the average distance of groups is ...
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27 views

Group comparison for extreme value data: which method is suitable?

I have measured Gaussian curvature data of 3D objects from two different groups, A and B. I would like to find out whether the objects differ in curvature. The distribution of data values for each ...
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1answer
22 views

How can I compare how significant is the difference between three or more distributions of count data?

I am researching whether software developers use different numbers of communication channels when performing different activities. Therefore, I would like to know whether, depending on the activity, ...
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15 views

Group comparison for bivariate distributions

For two groups A and B that consist of n and m individual samples. Each individual sample has a unique 2-dimensional joint probability density functions (PDFs)of two variables. These PDFs are ...
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1answer
28 views

The difference between means in t-test

When the sample size is large, the results tend to be statistically significant even when there is a small difference between the means of two groups. however, sometimes we see the results are not ...
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0answers
7 views

Test for difference from 0 for non-normal distribution

I'm using an agent based model to study disease transmission. After the initial outbreak, percentage of population infected decreases to zero. I'm looking for a rigorous way to choose when the % ...
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0answers
7 views

Comparison of two groups of time-series

I have time series data collected from two sensors. Suppose that they are microphone recordings from a man and a woman. Each signal, e.g. the one below, is 5000 samples. They don't share some ...
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3answers
75 views

Mixed models. Random slopes only, mean and group centering?

Are random intercepts a theoretical/practical prerequisite to random slopes? Why? I have a three level (rep measures) mixed model where I wouldn't expect lvl 3 variation in initial status of outcome ...
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1answer
491 views

Principal component analysis with non-independent observation

I have observations with 6 individual-level characteristics from 2000 units in 56 groups (villages). I know that within groups, characteristics are strongly related as individuals influence each other....
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11 views

Real (not rounded) Lower and Upper limits of groups of frequency distribution and Median for infinitely continuous data

From here on page 5: https://www.pbarrett.net/techpapers/percentiles.pdf So how can both be correct – yet seem to be more appropriate under different conditions? The clue is spread throughout the ...
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1answer
198 views

Different results doing mixed effects anova and post hoc tests of simple effects and paired T-test

I have run a mixed effects anova in r to look at the performance differences in two groups (control, patient) in 5 separate conditions. The conditions are my within subject factors. Group is the ...
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1answer
48 views

Whether there is significant difference between the slopes of different gender groups

The last question I have posted here: Whether there is significant difference between two gender groups There are 16 people in the dataset(using subjectID to ...
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1answer
12 views

Test that predicts group membership from multi-variate data?

Context: Zoology undergrad dissertation. The format of my results will be % time individual birds spent doing certain activities (and possibly number of times an activity such as pecking was performed)...
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1answer
35 views

Whether there is significant difference between two gender groups

A data set contains 5 columns: There are 16 people in the dataset(using subjectID to identify them). Each year, when these people were ages 11, 12, 13, 14, and 15, they provided us a score $y$. We ...
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1answer
18 views

Which Test should i run to check if there is any difference between variables?

I am analyzing one data set that contains 200 observations and contains information about two types or murders. It has 49 variables and I am interested in checking whether there is any difference ...
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1answer
18 views

Standardized Difference to compare prevalence between 4 groups

In this article, https://www.tandfonline.com/doi/abs/10.1080/03610910902859574 Peter Austin describes how to calculate the standardized difference between two groups, pg 1229 and pg 1230. However am ...
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0answers
11 views

Effect size on the difference between group differences (ΔA-B vs ΔA-C) using R

I am trying to calculate effect sizes, but all I can find on the web relates only to the effect size of the difference between two groups. What I am interested in, is the effect size of the difference ...
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1answer
199 views

ANOVA (assuming different distributions) vs Kruskall-Wallis and post-hoc tests

During stats courses on Uni I learnt (if I remember correctly and hopefully don't put my teachers to shame) that if you want to compare multiple groups with eachother you look at the residuals of an ...
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2answers
113 views

Male-female height difference estimation from thresholds

Introduction. Assume that two populations $A$ and $B$ are distributed with normal distributions $N(\mu_A, \sigma_A^2)$ and $N(\mu_B, \sigma_B^2)$. This is a general problem, but as an example, I will ...
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1answer
63 views

How to estimate the confidence interval of the difference of means?

I have two sets of measurements (repeated measurements of two processes, let's call them $X=\{X_i\}_{0...n}$ and $Y=\{Y_i\}_{0...m}$), and I would like to estimate (with confidence interval) the ...
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0answers
10 views

Estimation of substitution effect

I have a market with three goods: PRODUCT_I,PRODUCT_II, PRODUCT_III. PRODUCT_I is banned by a policy, and its sales brought down to 0. I want to estimate to what extent PRODUCT_II and/or PRODUCT_III ...
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1answer
196 views

How to find groups in data divided by difference in one variable?

I`ve got a question concerning Student Alcohol Consumption dataset. http://archive.ics.uci.edu/ml/datasets/STUDENT%20ALCOHOL%20CONSUMPTION Please, help me to realize which methods\models (python and ...
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0answers
35 views

Grouped data as independent variable for continuous outcome

I have an independent variable grouped into irregularly sized classes (0, 1-5, 6-10, 11-20, >20), a continuous dependent variable, and several control variables. So far I've been trying to stay close ...
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1answer
19 views

Differences between sexes across months with repeated IDs

I'm trying to figure out the best way to analyze the difference between sexes and across months for the means of a specific behavior (most individuals measured have repeated measures across the 5 ...
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0answers
11 views

Comparing groups of empirical probability density functions

I'm a neuroscientist approaching doing some complex statistics and can't find anyone to point me in the right direction of what I need. I'm happy to read around the subject, I just don't know enough ...
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2answers
52 views

What is the variance of the standardized mean difference of two independent studies?

I have computed the standardized mean differences for a pair of independent samples. But when I Googled for the "variance of the standardized mean difference" I got rather confusing results, with ...
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0answers
11 views

What can I use to compute a similarity (or diversity) index for a sample with “multidimensional” attributes?

Current problem: We have a batch of $n$ items for which we capture their details with $m$ attributes. It could look something like this: The goal is to compute an "index" that says how "similar" this ...
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2answers
63 views

How do you perform Wilcoxon matched-pair sign-rank test in Stata using a grouping variable? [closed]

I'm performing a diagnostic method comparison study in which I have 2 groups; one assessed using the experimental method, and one assessed using the standard method. These groups are matched, with 3 ...
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1answer
22 views

Difference between two dependent variable with two covariates

I have two groups (A & B). First step In each group, I am trying to find the relationships between dependent variable (flow) and 2 covariates (total rain and preflow). Should I: Do a multiple ...
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0answers
22 views

Compare slopes between two groups of equal size

I want to compare how does a dependent variable (total flow) changes with a covariate (total rain) between two groups (stream A & B). Usually, i would go with ANCOVA. But these groups have the ...
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0answers
13 views

Appropriate method to assess scatter or variation in groups with dramatically different means

I am working on a product fabrication process, and I want to demonstrate the consistency of my product. To do this, I am trying to measure the variation in the extent to which a biological material is ...
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1answer
19 views

Detecting significant changes in groups of values over certain ranges of time-series

Below is an example of data output. It represents indicies [y-axis] calculated for 52 weeks in a range of 64 years. Group of 64 years is classified and several years are represented with blue, some ...
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0answers
17 views

Analysis of repeated measures at different timing

I'd like to ask how can analyse data of different patients if they have repeated measures at different timing. How can I group repeated measures to each patient in order to have descriptive data of ...
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0answers
26 views

How does one show differences in groups with replicates over time in R

I have daily Hydrogen production data and nutrient uptake data. I would like to show differences in treatments for Hydrogen production over the course of 3 days. Basically identify which group ...
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0answers
59 views

Test selection: Biserial correlation versus independent samples t-test?

My stats textbook is telling me that you can use a Pearson's r with a dichotomous variable and a continuous dependent variable, which is known as a biserial correlation (or point-biserial if the ...