Help -Inference about interaction coefficients in two-factor study

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SUMMARY

This discussion focuses on testing interaction coefficients in a two-factor study involving gene responses and disease presence. The full model is defined as y_{gtk}=\mu+\alpha_g+\beta_t +(\alpha\beta)_{gt}+\epsilon_{gtk}. To test the null hypothesis H_0 : (\alpha\beta)_{25,t}=0 for gene g=25, the participant suggests creating a dummy variable for gene 25 and interacting it with the disease factor. This approach allows for a focused analysis without dropping the entire factor.

PREREQUISITES
  • Understanding of two-factor ANOVA models
  • Familiarity with hypothesis testing in statistical analysis
  • Knowledge of interaction terms in regression models
  • Experience with statistical software for model fitting (e.g., R or Python)
NEXT STEPS
  • Learn how to implement interaction terms in R using the lm() function
  • Study hypothesis testing techniques for interaction effects in ANOVA
  • Explore the use of dummy variables in regression analysis
  • Investigate model comparison methods, such as ANOVA or likelihood ratio tests
USEFUL FOR

Researchers in genetics, statisticians analyzing gene-disease interactions, and data scientists working with two-factor experimental designs.

solar42
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I have measurements of some response of a gene, and two factors: the gene, g=1...G and whether the patient/subject has a certain disease, t=1,2.

the full model is
[tex] y_{gtk}=\mu+\alpha_g+\beta_t +(\alpha\beta)_{gt}+\epsilon_{gtk}<br /> [/tex]

I know that to see if genes have any connection at all with the disease, I just fit the reduced model without the [tex](\alpha\beta)_{gt}[/tex] interaction and compare the two, but if I want to see if, say, gene number g=25 has anything to do with the disease... I know that the null hypothesis is [tex]H_0 : (\alpha\beta)_{25,t}=0, \textrm{ for all } t[/tex], but how do I test this hypothesis? I am confused at what to do when I can't drop the whole factor and compare.
 
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You can define a separate "dummy" variable for gene 25 and interact it with the disease.

EnumaElish
 
Last edited:

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