assumptions

I always thought that we should be testing the assumption of normality by looking at the distribution of the DV in our design (by each level of the IV). But I keep seeing people talking about the residuals of the DV. For example, in ANOVA (and I suppose by extension the t-test and regression)...

Hello, I’m writing my thesis about the question: is ruminative thinking an independent risk factor for predicting marihuana use (controlled for sex and depression). In this study there are 300 participants of which 60 used marihuana. To investigate this relationship I wanted to do a multiple...

I am trying to run a binomial logistic regression, and would like to check the linearity assumption. However all the resources I'm reading discuss the procedure for continuous variables, and I am only working with ordinal/categorical predictors. Can someone take me through it step by step, or...

Hallo there :wave:, I am examining the difference in illness models (by asking several questions: DV) for refugees and non-refugees (IV) (both n= 100). In addition, we asked about several confounding variables / covariates (demographic data). I hypothesis that DV (illness model) will differ...

Hallo there :wave:, I am examining the difference in illness models (by asking several Likert scale type questions: DV) for refugees (n=100) and non-refugees (IV)(n=100). In addition, we asked about several confounding variables / covariates (demographic data). I hypothesis that the illness...

Do parametric tests make assumptions regarding linearity? Whether yes or no, how can I explain this? It seems to me as though regression analyses assume linearity, but I can't seem to figure out whether these can be parametric tests or not. Many thanks!

Hi, What is the non parametric alternative for parametric ANCOVA if we find that some ANCOVA assumptions are not met? How it can be done in SAS?

Hello, I've ran a 2x2 anova and am trying to report the assumptions but would like to make sure ive done it correct, statistics is my weak point! I have tested normality and homogeneity and also tested for skew and kurtosis. Then am I supposed to report the means and the significance levels...

I have a dataset in which I am performing linear regression with multiple covariates. The goal of the analysis is to identify important covariates (categorical and continuous) which have an important effect on the response. This is a natural resource dataset so it is not as clean cut as other...

I was watching [Hadley's dplyr video](https://www.youtube.com/watch?v=8SGif63VW6E) and he said a statement that made me think: 8SGif63VW6E#t=134 I asked for clarification via Twitter and he said: I'm curious what others think about these comments. Do people agree? Is he saying the model...

Hello Everyone, I'm a grad student in biostatistics and am currently working at my first job with real world data. I'm analyzing survey data accessing employee's comfort with their work environment (DV) by several characteristics (IVs) (e.g., sex, race, religion). The DV, Comfort, is...

Hello all, I am new to the forum. I had a bit of training in statistics and research, particularly statistics in psychology, but I have some basic questions that are holding me back. I would appreciate the help. 1. How can I determine the ideal sample size for a study (upper and lower...

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Hello, I feel like the answer for this is probably really obvious but I am being missing it altogether. This is my data: Habitat Associating Not Associating Total Observations Flood 51 0 51 Levee 524 72 596 Liana 162...

Hi, I would really appreciate some help with this. I am looking to see if employees' organisational history (such as voluntary/involuntary turnover) and their contract type (part or full-time) impacts on their organisational commitment and empowerment. So I have 2 Dependent Variables...

Hi, I would really appreciate some help with this. I am looking to see if employees' organisational history (such as voluntary/involuntary turnover) and their contract type (part or full-time) impacts on their organisational commitment and empowerment. So I have 2 Dependent Variables...

In anova, we assume that the random error term \epsilon_{ij} is independent and identically distributed with mean 0 and variance \sigma^2 How can I check the normality assumption and independence assumption? Does model adequacy checking mean "Checking the normality assumption that...

1. I could google this but in my past searches I get conflicting stuff and wrong stuff. So I'll state what I think are the assumptions of ANOVA & their meanings and ask you all to add or critique. I'm taking this from Cohen, Cohen Aiken and West a) Correct specification of the form of the...

Hi everybody :) I ended up asking a few questions in another thread that however didn't have a matching title, which probably explains why nobody replies. Since it's really important for me to understand, I am reposting my questions in this new thread with a matching title... and hope someone...

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