10. Demonstrating Equivalence

Introduction to Sample Size Calculation
Training session with Dr Helen Brown, Senior Statistician, at The Roslin Institute, January 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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A spreadsheet to carry out the calculations described in the presentation may be copied here: datashare.is.ed...
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*Recommended UA-cam playback settings for the best viewing experience: 1080p HD
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Content:
What if objective is to demonstrate equivalence?
To show 2 treatments are equivalent, not different
Possible hypothesis to test:
--- 95% confidence interval of difference (or ratio) of means is within specified range
--- Eg 95% CI of ratio of 2 treatment means within 0.8 to 1.2
----- often used for bioequivalence studies in clinical trials
Example: How many mice to demonstrate equivalence of 2 injections on red blood cell count (RBC)?
Objective: to demonstrate equivalence of 2 injections
---eg equivalence concluded if difference in RBC means smaller than 0.40
---require 95% CI to be within (-0.40, 0.40)