CH. 8 Flashcards
Value (in animal breeding)
Any measure applied to an individual as opposed to a pop. Exs. are phenotypic value, genotypic value, breeding value, and environmental effect,
Population Measure
Any measure applied to a population as opposed to an individual
Population Parameter
A true (as opposed to estimated) population measure. Exs. are true population means, variances, and standard deviation; true correlations between traits; and true heritabilities
Sample Statistic
An estimate of a population parameter
Normal Distribution
The statistical distribution that appears graphically as a symmetric, bell-shaped curve
Mean
an arithmetic average
Variation (in most animal breeding applications)
differences among individuals within a population
Variance
A mathematical measure of variation
Standard Deviation
a mathematical measure of variation that can be thought of as an avg. deviation from the mean. The square root of the variance
Variable
Any quantity that can take on different numerical values. All elements (except mean) of the genetic model for quantitative traits- P, BV, E, etc. are considered variables
Covariation
How two traits or values vary together in a pop
Covariance (cov(X,Y))
the basic measure of covariation
Correlation Coefficient
A measure of the strength (consistency, reliability) of the relationship between two variables.
Phenotypic Correlation
A measure of the strength (consistency, reliability) of the relationship between performance in one trait and performance in another trait
Genetic Correlation
A measure of the strength (consistency, reliability) of the relationship between breeding values for one trait and breeding values for another trait
Environmental Correlation
A measure of the strength (consistency, reliability) of the relationship between environmental effects on one trait and environmental effects on another trait
Regression Coefficient
The expected or avg. change in one variable (Y) per unit change in another (X)
True Values
An unknown, underlying attribute that affects animal performance. Exs. include breeding value, progeny difference, gene combination value, producing ability, environmental effect, etc.
Predicted Value
A prediction of a true value. The most common predicted values are estimated breeding value, expected progeny difference, and most probable producing ability
Prediction Equation
A mathematical equation used to calculate a predicted value based (usually) on phenotypic data.
