Questions tagged [group-differences]
Group differences broadly refer to statistics which quantify the differences between two or more subpopulations.
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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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10 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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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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51 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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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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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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26 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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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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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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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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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
74 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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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
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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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
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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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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2answers
110 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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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
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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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
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
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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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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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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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
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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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2answers
59 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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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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25 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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58 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 ...
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17 views
How to define the cut off point?
I have population of 218 people operated on after a certain event. They are operated on from day 30 to day 911 after the event . Some of them were OK (0) and some got a complication (1). I would like ...
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1answer
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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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35 views
T-test for differentially expressed proteins in R?
I hope I am asking to the right place. I am currently analyzing some Mass Spectometry data of 2 mutant phenotypes and the WT with 5 biological replicates each.
I have normalized the abundance values ...
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0answers
24 views
Pair-wise ANOVA or non-parametric comparison
I'm doing an experiment with 7 groups (batches) of 12 measurements of a certain chemical, where one group (b0) is considered the baseline case. The research question is to find out which groups have ...
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12 views
Statistics to show the differences in population of the sample and city and by sex
Hoping for some help. I am trying to run some statistics for demographics from the results of a survey. I have male/female percentages as a result of the survey (45.1/54.9) compared to male/female ...
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246 views
Comparing sum of values of two groups
I have a question about how to make a comparison between the aggregate values of two experimental groups.
Say that in an experiment with a control group and a treatment I collect the number of times ...
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2answers
34 views
Is this a matched pairs data set?
A review problem for one of my daughter's statistics classes: The arm span and height of 10 individuals is measured in order to test the hypothesis that arm-span equals height in humans. Perform an ...
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1answer
55 views
How do you test if three means significantly differ from each other using an F test?
I know the means, sample sizes, and standard deviations of three samples drawn independently from three populations. I need to test whether they differ significantly from each other using an $F$ ...
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13 views
Survey subgroup difference from entire survey or excluding the subgroup?
I have a survey with categorical (nominal) questions. I want to compare subgroups to see if any are noticeably different from each other.
Suppose they are ranking their preferred three from ten ...
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19 views
Comparing statistics over win/loss
I have data from a league over a season. The season was conducted as a round robin so everyone played each other. Each game was a best of 5 so at the least a game produced 3 matches and at the most ...
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15 views
Porbability of an observation to belong to a specific group
I have a group with about 200 observations,and each observation has 2 variables (which are the first two components of PLS, if it matters). It looks like this:
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90 views
Find significantly differences between multi-variant groups
I have 11 groups, each consist of about 200 observations, and each observation has 2 variables (which are actually the first two PLS components if it makes any difference). Each group is a substance ...
