Which variable is typically excluded from the model when calculating for a non-repeated trait?

Which variable is typically excluded from the model when calculating for a non-repeated trait?

• A. Genetic factors
• B. Temporary environmental factors
• C. Permanent environmental influences
• D. Breeding value

Answer: (B)

When calculating for a non-repeated trait, the variable that is typically excluded from the model is temporary environmental factors. Non-repeated traits are those that are measured only once per individual, such as height or weight at a certain age. In these analyses, the focus is on the more stable influences on the trait, such as genetic factors and permanent environmental influences, since temporary environmental factors, which might cause fluctuating measurements, do not provide reliable information for a one-off measurement.

Including temporary environmental factors would introduce additional variability that is not related to the underlying genetic or permanent environmental influences, making it difficult to assess the true genetic potential or environmental contributions to the trait. By excluding these factors, researchers can obtain a clearer picture of the genetic influences that contribute to the trait being measured.