Linked Questions

2 votes
2 answers
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 ...
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1 vote
2 answers
482 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 ...
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  • 131
0 votes
0 answers
293 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
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84 votes
4 answers
52k 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 ...
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  • 2,640
46 votes
2 answers
59k 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 ...
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  • 479
27 votes
4 answers
42k 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 ...
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  • 271
32 votes
2 answers
71k 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 ...
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  • 599
23 votes
4 answers
16k 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'...
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  • 748
16 votes
3 answers
43k 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 ...
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  • 273
11 votes
2 answers
8k 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 ...
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9 votes
2 answers
17k 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 ...
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10 votes
2 answers
24k 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 ...
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13 votes
2 answers
14k 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 ...
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  • 131
12 votes
2 answers
7k 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 ...
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  • 497
9 votes
3 answers
13k views

How to interpret this shape of QQ plot of standardized residuals?

I am running linear regression for a continuous variable (not standardized) with age and 2 other numeric continuous variables (not standardized), 2 categorical variables with 3 levels each and 1 ...
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  • 8,993

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