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Merck Manual
Veterinary Manual
The trusted provider of veterinary information since 1955

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VETERINARY PET
Calculating an Odds Ratio

Calculating an Odds Ratio

Outcome Status

+

−

Exposure Status

+

a

b

−

c

d

a = Number of exposed cases

b = Number of exposed noncases

c = Number of unexposed cases

d = Number of unexposed noncases

Merck & Co., Inc., Rahway, NJ, USA (known as MSD outside of the US and Canada) is dedicated to using the power of leading-edge science to save and improve lives around the world.  The Merck Veterinary Manual was first published in 1955 as a service to the community.  The legacy of this great resource continues as the Merck Veterinary Manual in the US and Canada and the MSD Vet Manual outside of North America.

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