635 views

If one group has 23 participants and the second group has 117 participants in it, can we rely on the result of t-test? [duplicate]

I was evaluating a research paper in which the authors have 23 male participants and 117 female participants. They have applied t-test to calculate Gender differences and have even concluded on ...
• 21
1 vote
662 views

T-test with equal variance but large, unequal sample sizes [duplicate]

For an independent samples t-test, I have two groups with equal variance (Levene's not significant) but the sample sizes are quite different. Example one: Group one N = 366 ; Group Two N = 174. ...
• 11
45 views

Is GLM appropriate for an extreme unbalanced dataset? [duplicate]

I have a dataset with 174 females and 28 males. I am interested in the gender differences, as well as the interactions between gender and other factors, in a continuous dependent variable. Is GLM ...
58k views

Unequal sample sizes: When to call it quits

I'm peer reviewing an academic journal article and the authors wrote the following as justification for not reporting any inferential statistics (I deidentified the nature of the two groups): In ...
• 163
22k views

Power of the t-test under unequal sample sizes

I heard that the power of a t-test used with unequal samples is limited by the size of the smaller sample. Can I take this to mean that the power of a t-test with unequal sample sizes is equal to the ...
• 1,183
25k 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 ...
• 235
1k views

Using computer simulations to better understand statistical concepts at the graduate level

Hi I'm taking a graduate course in Statistics and we've been covering Test statistics, and other concepts. However, I am often able to apply the formulas and develop a sort-of intuition on how stuff ...
• 2,025
3k views

Experiment or simulation to undestand type I and type II errors

I am studying Type I and Type II errors and basic concepts of testing hypotheses. To better develop my intuition I would like to write a few simple simulations. What I'm hoping is to get a base ...
• 2,025
17k views

Unequal sample size one way ANOVA [duplicate]

I want to compare the means of X between BMI groups, but have unequal sample sizes between my groups. ...
• 63
7k views

Unbalanced distribution of sample size between groups in logistic regression: should one worry?

I need to fit logistic regression models to a dataset where infection (present/absent) is my dependent variable and neighborhood (three factors: Rich, Poor, Very Poor) my independent variable. ...
• 619
2k views

Are unequal groups a problem for one-way ANOVA?

I have data for three unequal groups: $N = 44$, $N = 354$ and $N = 347$. Is it possible to compare all three groups running a one-way ANOVA or is the first group too small?
• 103
4k views

Mann-Whitney U test with unequal group sizes and one group very small

I have a sample of 24 participants who gave their responses to 8 questions. I calculated their mean response. Can I use Mann Whitney to compare between 2 groups where one of them has only 2 ...
621 views

Multiple linear regression where explanatory variables almost always equal 0

I'm trying to do a multiple linear regression model to correlate a dependent $Y$ variable (normally distributed) against a set of 642 variables. These 642 variables codify for the presence or absence ...
• 73
10k views

MANOVA with unequal sample sizes

I have data for 352 response ratings that have been categorized as "Low," "Medium," and "High." I would like to compare the differences of five variables across the three categories to see which ones ...
• 71