Linked Questions

2
votes
2answers
4k views

Unequal sample sizes one-way ANOVA [duplicate]

I have a question about a data analysis that I am running. I am analyzing the results of a survey in which (expectedly) there exists far fewer people in one group than in another. This survey is an ...
1
vote
2answers
351 views

When can we use ANOVA test? [duplicate]

We want to verify if the means of the 3 samples are equal. When we test the homogeneity through Bartlett test we get that the hypothesis is rejected. Can we apply ANOVA test? (we applied ANOVA test ...
0
votes
0answers
207 views

Ancova for unequal variances [duplicate]

What is the best way to compare two non-homogeinous populations (Levene's) with covariates (e.g. age). I know ancova assumes homogeneity. Is there a way around this? Many thanks
77
votes
4answers
43k views

Can bootstrap be seen as a “cure” for the small sample size?

This question has been triggered by something I read in this graduate-level statistics textbook and also (independently) heard during this presentation at a statistical seminar. In both cases, the ...
24
votes
4answers
36k views

Best way to deal with heteroscedasticity?

I have a plot of residual values of a linear model in function of the fitted values where the heteroscedasticity is very clear. However I'm not sure how I should proceed now because as far as I ...
27
votes
2answers
62k views

How do you find weights for weighted least squares regression?

I am a bit lost in the process of WLS regression. I have been given dataset and my task is to test whether there is heteroscedascity, and if so I should run WLS regression. I have carried out the ...
21
votes
4answers
13k views

Practically speaking, how do people handle ANOVA when the data doesn't quite meet assumptions?

This isn't a strictly stats question--I can read all the textbooks about ANOVA assumptions--I'm trying to figure out how actual working analysts handle data that doesn't quite meet the assumptions. I'...
39
votes
1answer
51k views

Determining sample size necessary for bootstrap method / Proposed Method

I know this is a rather hot topic where no one really can give a simple answer for. Nevertheless I am wondering if the following approach couldn’t be useful. The bootstrap method is only useful if ...
16
votes
3answers
38k views

Alternative to One-way ANOVA unequal variance

I would like to compare the means across three groups of equal sizes (equal sample size is small, 21). The means of each group are normally distributed, but their variances are unequal (tested via ...
11
votes
2answers
6k views

Is it wrong to use ANOVA instead of a t-test for comparing two means?

I have a distribution of salaries and I want to compare the difference in means for males and females. I know there's the student T-test for comparing two means but after suggesting ANOVA I received ...
9
votes
2answers
12k views

Will log transformation always mitigate heteroskedasticity?

Will log transformation always mitigate heteroskedasticity? Because the textbook states that log transformation often reduces the heteroskedasticity. So, I want to know in which cases it won't lessen ...
12
votes
2answers
12k views

Bartlett's test vs Levene's test

I am currently trying to address violations to ANOVA assumptions. I have used Shapiro-Wilk to test normality, and have dabbled with both Levene's test and Bartlett's test of variance equality. I have ...
8
votes
2answers
22k views

How can you test homogeneity of variance of two groups with different sample sizes?

I have two groups of data that have different sample sizes and in order to be able to analyze both sets they must have the same variance. I was told I should use Bartlett's to test the homogeneity of ...
11
votes
2answers
6k views

How to get ANOVA table with robust standard errors?

I am running a pooled OLS regression using the plm package in R. Though, my question is more about basic statistics, so I try posting it here first ;) Since my regression results yield ...
5
votes
4answers
13k views

Bootstrap two-sample t test

I'd like to bootstrap a two sample t-test. My DV is some psychological variable. I have two groups (women and men), unequal sizes and I do not assume equal variances. I'm not sure if my code or/and my ...

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