Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [group-differences]

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

3
votes
0answers
13 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 ...
1
vote
0answers
9 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 ...
0
votes
1answer
19 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 ...
3
votes
0answers
19 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 ...
0
votes
0answers
8 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 ...
2
votes
2answers
29 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 ...
0
votes
0answers
15 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 ...
0
votes
0answers
23 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 ...
0
votes
0answers
18 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 ...
1
vote
0answers
15 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 ...
0
votes
1answer
16 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 ...
0
votes
0answers
24 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 ...
0
votes
0answers
23 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 ...
0
votes
0answers
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 ...
0
votes
0answers
71 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 ...
0
votes
2answers
26 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 ...
2
votes
1answer
47 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 $F$ ...
0
votes
0answers
12 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 ...
0
votes
0answers
16 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 ...
0
votes
0answers
12 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: ...
1
vote
0answers
31 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 ...
0
votes
1answer
30 views

analyzing difference between two groups by other numeric factor with only (0-5) values

I want to analyze the difference between two groups by other factor. the factor is numeric with distribution (0-5) only. using Stata® what would be the best test to estimate the significance of ...
1
vote
0answers
46 views

Weibull coefficients comparison [closed]

I´ve 838 sets of data that represents points distributed by height. Those that can be fitted by Weibull function. So, I normalized them and adjusted the corresponding distribution function, saving it´...
0
votes
1answer
47 views

Differences between exponential distribution with very different n sizes

I need to test for the differences between three groups of observations (grouped along $x$-axis), which appear to follow an exponential distribution along the $y$-axis dimension (see example fig.). ...
0
votes
1answer
29 views

Comparing the results of 2 different type but identical samples from 2 devices

I have 2 columns of of the concentration of fat in fish which is measured by 2 different labs. I need to know if the difference of the results from these 2 labs are statistically significant. The data ...
0
votes
1answer
16 views

Sample size for 2 groups vs. one large group to measure spread?

I hope this question can simply be answered conceptually, without a specific dataset. I am planning a new study, for which I will be testing the effects of depression on a memory task. I'm currently ...
1
vote
0answers
52 views

Comparing the means of two groups when a large number of data points have the same value

I have data on the profitability of wagers made according to two different strategies. One strategy was to bet $1 on the underdogs in each of a sequence of sporting matches. They have data like this: ...
1
vote
0answers
39 views

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") ...
0
votes
0answers
23 views

How to test for difference in weighted proportion difference? (and average weighted proportion differences)

Suppose I have a survey where respondents rate different questions as positive (1), negative (-1), or neutral (0), and their responses are given a different weight based on which job they have and ...
1
vote
0answers
20 views

Randomized Treatment within treated group

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 ...
1
vote
0answers
63 views

T-test with nested data

I want to test gender differences in an outcome variable called the willingness to pay. My data consists of records with following three fields: ...
0
votes
1answer
58 views

How to apply fixed effects in R?

In this example they just want to know if the announcement decreases the trading assets ratio. What are fixed effect in application here? Meaning of quarter and companies fixed effect? How they keep ...
0
votes
0answers
30 views

Which test to use to detect difference in proportion between more than 2 groups? Logistic regression?

I have data that looks like this: there is a group of 27 subjects with one dichotomous variable y1 at 3 times points. The propbability of y1 is different between the 3 time points (100%, 85%, and 40% ...
0
votes
0answers
16 views

Compare principal components/differences between two groups

I have four groups of individuals which have a certain illness and are part of a clinical trial: Taking drug, illness gets better Taking drug, illness is not getting better Taking placebo, illness ...
0
votes
0answers
44 views

How to statistically model this group difference?

I am studying if men and women consumers differ in how attractive they find product advertisements written differently. I am specifically looking at positive and negative sentiments as two ...
1
vote
0answers
58 views

Test if mean of one group is significantly different from means of several other groups [closed]

In my experiment I have a number of clusters of cells from an unsupervised clustering. Each cluster represents a cell type, and can be seen as random samples from a large pool of possible cell types ...
0
votes
0answers
12 views

Running analyses with uneven group sizes [duplicate]

I was trying to run a study with 100 people per condition for 4 conditions. When I looked at the results, the group sizes were skewed - some had 80, some had 120. If I'm planning on running a series ...
0
votes
0answers
12 views

Hypothesis test on differences in absolute effect size (difference in difference in means) with skewed data

I am comparing highly-correlated ways to classify patients as positive or negative for a disease. I classify patients as positive or negative under disease definitions 1, 2, ... and then look at the ...
2
votes
1answer
21 views

Test of difference maximum likelihood parameters SEM R

I have a structural equation model implemented in R 3.4.4 using lavaan 0.6-1 and estimated on two different subgroups using a robust maximum likelihood estimator. Now I want to compare the parameters ...
0
votes
0answers
11 views

Group comparison after clustering (without using statistical tests)

I have a dataset whose variables can be grouped in variable sets (VS) 1 and 2. VS1 represents blood parameters, VS2 other phenotypic data. Variables in VS1 are standardized to N(0,1). I have ...
0
votes
0answers
26 views

Group comparision in repeated measures data with missing values?

I have data from blood samples collected from 20 patients before, during (at 30 min, 1 h, 2 h, 3 h, 4 h) and after a medical treatment (using the slightly different treatment protocols A and B). The ...
1
vote
0answers
29 views

Comparing observed and expected diets of two different species

My data consists of dietary data from two species (C1 and C2) and expected diets for each species (E1, E2) generated from a combination of variables, but is based on their foraging behavior. What I ...
0
votes
0answers
15 views

Compare occurrence of events

I have two groups of samples (A = 25 samples and B = 40 samples). In both of these groups can happen a series of events (or a series of groups of events classified as n-grams) that can happen ...
1
vote
0answers
43 views

Is log based transform comparable across groups with different minimum values?

I have data for different groups that includes positive, negative, and zero values. Here is an example: group1: c(-503583,-395833,0.1,3835,19,-0.001,0,48400883) group2: c(-39,-8340,-10,0,0.1,2889,93,...
1
vote
0answers
46 views

Difference in distribution of multinomial distributions

I have some questions regarding how to analyse catagorical data, summarised as percentages on an individual level. In the data in question, for each individual we know the fraction of biological ...
1
vote
0answers
29 views

Combining intra and inter cohort comparison using panel-data

After reading numerous posts, I still haven't found a conclusive answer to my question. I have panel data for the whole population(multiple years, interlinked by personal identification numbers), ...
0
votes
0answers
25 views

How to compare the grouped random forest importance across different models?

I have a modeling problem where I have a reasonably large number of features (~75) that can be separated into 3 broad classes. These features correspond to field plots where measurements were taken. ...
2
votes
1answer
293 views

Jonckheere-Terpstra test: two-sided and one-sided, directed and undirected hypotheses

I need to perform a Jonckheere-Terpstra test, but I am not sure how to do it and how to interpret the results. I have following data: Three groups doctors1, doctors2, doctors3 And how often they ask ...
0
votes
0answers
66 views

Conclusion on which groups differ without doing post-hoc test

If you do a statistical test that compares groups and find a significant difference between groups, can you then conclude that there is a difference between the "lowest" group and the "highest" group, ...
0
votes
0answers
22 views

Comparison of unbalanced groups of values

I know there are several questions (here and on other websites) regarding the comparison of values, but I am still lost with the data I have and the analyses I should conduct. I have just 18 values (...