9. Trials Involving Comparisons Between Units

Introduction to Mixed Models
Training session with Dr Helen Brown, Senior Statistician, at The Roslin Institute, March 2016.
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These training sessions were given to staff and research students at the Roslin Institute. The material is also used for the Animal Biosciences MSc course taught at the Institute.
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*Recommended UA-cam playback settings for the best viewing experience: 1080p HD
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Content:
Trials involving comparisons within units (eg animals)
Eg:
--- Animals observed: Pre-treatment
6, 12 and 24 hours post-treatment
--- Objective - compare pre-treatment to post-treatment values
Complete data:
--- Paired t-tests, or a general linear model GLM satisfactory
Missing data:
--- Mixed model provides more accurate estimates and more sensitive tests
----- animal effects random
----- information from animals with missing data included