9. Allowing for Drop-outs

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:
Allowing for drop-outs
Sometimes data are missing
---Eg animals die or move before study is complete
---Measurements not taken, or taken incorrectly
Build into sample size calculation, eg
---Calculate 20 animals per group
---10% drop-out or missing data expected
---Increase number by 10% to 22 per group