Questions tagged [group-differences]

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

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Two-sample bootstrap?

I have two independent samples of observations. From each sample I produce a statistic. Let's denote these as $\theta_1$ and $\theta_2$. I'd like to test the hypothesis that $H_0: \Theta_1=\Theta_2$, ...
3k views

Comparing the result of a study which has unequal group sizes

I have conducted two user studies and in my studies I didn't have control over the group sizes. In each study users were put in groups and they were asked to perform some group activities. Here is the ...
23 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 ...
53 views

Doing the equivalent of a dependent t-test on a sample of correlation coefficients

I’m doing an analogy of the following study. I take participants etc. and show them a picture of man 1 and have them rate his attractiveness and rate his intelligence just from his picture. I then ...
120 views

Time series group comparison

I am currently analyzing a time-series experiment and I have some difficulties to come with a nice comparison of my groups. I was hoping someone could help me. The design is the following: Three ...
107 views

Determine Chi Square Group Differences in multiple choice questionnaire

I'm trying to determine if there is a group difference in answering a multiple choice question. For example, I want to answer the question of, do "Change Instigators" (group A) answer "communication"...
389 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)...
267 views

Intuition behind fixed effects

Im trying to explain the intuition behind fixed effects to a group of people with no background in (formal) regression analysis. Explaining the intuition behind Diff-in-Diff estimation of the impact ...
33 views

Test for participant subgroups in gradual means shift

In an experiment with 44 participants I have measured the response time for a set of stimuli, where the response could be a or b. The means of the two responses do not differ significantly (783.3 vs ...
4k views

Averaging z scores when doing a “group by”

I have a dataset where each row is an hourly measurement of certain fields (columns). For each column I then add another column that is its respective z score relative to the entire population. If I ...
422 views

Using similarity matrix to measure diversity of a group

I wish to measure the "diversity" of a group of objects. Right now I'm using Euclidean distance to compute the similarity matrix between all the objects in the group. I'm searching for a measure of ...
369 views

Heterogeneous Treatment Effects - How to test differences in the ATE?

I want to conduct a simple propensity score estimation where the treatment $D_i$ is a binary variable ($D_i=1$ individual $i$ participates in the labor market program, zero otherwise). I estimate the ...
154 views

How to measure the effect of users' participation in forums?

My problem is how to measure the effect of a user's participation in forums. I calculate the user's participation as the number of discussions that user posted. My hypothesis that a users' ...
250 views

Testing difference in proportions with bootstrap

Summary: I want to perform a bootstrap test on the difference of proportions. I think this is equivalent to testing the difference between means using bootstrap, but I wanted to clarify some details. ...
79 views

How many times should I difference a dataset?

Im currently reading The Foundation of Modern Time Series Analysis by Terrence C. Mills. In the fourth chapter he discusses the concept of difference data to remove secular trend and the history ...
92 views

Can I fit a linear mixed effects model to these grouped data?

Data and Objective The data are about lane change maneuvers. I want to predict the lane change duration of a driver of certain age and gender. Following is a very small subset of observations and ...
55 views

Comparing means between several groups

I am asking for your help. I have 3 variables that are divided into 4 groups (Quantitative variables). I intend to check if there is any difference between the groups for each variable. My ...
577 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....
80 views

How do I test for a difference in the standard deviations of two groups?

I have two groups and I want to know if there is a difference in standard deviation (or variance if it's easier) for each parameter. Here is a table of descriptive statistics for my data: After ...
1k views

Friedman test for a repeated measures experiment with replicates

(Please see example with reproducible data at the end) I have a data file with the results of an exercise performed 16 times with each of 2 control devices by 3 subjects. I measured the task ...
83 views

Group wise imputations allowed?

What is the correct way of imputing missing values? We are trying to predict the label of persons belonging to group A or B. The alternative hypothesis is that there are differences in parameters for ...
146 views

Generating predicted mean values and CIs across different groups in lme4

I’ve run a mixed-effects model with crossed random effects in glmer and ultimately want to show a bar graph depicting mean predicted values (and associated confidence intervals) across years within ...
373 views

When/how should I bucket/recode/group certain categorical levels in an “others” level?

Imagine I have a dataset with a categorical variable with many levels, and I want to use this dataset for binary (positive/negative) supervised learning. In this categorical variable certain levels ...
23 views

Find significantly different element

I have following data and want to know is there really significant difference between those five objects: I have 5 objects and 3 different tests and their results like this. So this is very few rows ...
471 views

Comparing differences between overlapping groups

I am trying to analyse the differences between people who vote in the European Parliament (EP) elections and people who vote in national elections, based on the EES dataset (http://eeshomepage.net/). ...
74 views

Determine how much and why a sample differs from its population

I'd like to be able to determine a) how much and b) why a non-random sample “differs” from the population (there's probably a better word than “differs”; I was tempted to use “does not represent” but ...
2k views

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Time Series sampled at varying frequency - Employ Linear Mixed Model to compare trends?

I hope that this question has not be asked like this elsewhere, if so I could not find it during my google research.. I have the following problem: I have data sampled from different sensors("ID") ...
I don't know if this situation has a particular name. I'll just give the example and my question. Suppose we have two naturally concurring groups, $A$ and $B$. By that, I mean there is a naturalistic ...