exam 2 Flashcards
what are statistics used for? (3)
evaluating numbers
describing the population
estimating unknown value
what are traits measured for? (2)
continuous variation or didcontinuous variation
what are some characteristics of continuous variation?
quantitative traits, many genes, small gradations, economically important, and tightly complex.
what are some examples of continuous variation.
weight gain and fertility
what is a sample used for?
it analyzes data from a population
what is the population perameter?
it describes the populatiom
what is a sample statistic?
a numerical descriptive measure of a sample
what does the central tendancy mean?
when values cluster at a midpoint and thins out at both extremes evenly.
define median, mean, and mode
median- halfway value between two extremes
mean- average
mode- class with the highest frequency
what is variance?
a measure of distribution
what is the equation for variance?
s^2=(Σ(x-x̄)^2)/(n-1)
what is the most useful statistic?
the mean
what are the three measurements of dispersion?
variance, standard deviation, and standard error
what is the equation for standard deviation?
squared root of s^2
what is the equation for standard error?
se= standard deviation/the square root of n
what is correlation?
a measure of relationship between two variables
what is the correlation equation?
r=(Σxy-(Σx Σy)/n)/the square root of (Σx^2-(Σx)^2/n)(Σy^2-(Σy)^2/n)
what are the ranges for correlation and what does it mean?
low- .01-.2
medium- .21-.4
high- >.41
what is the phenotypic correlation?
strength of relationship between the performance in one trait and the performance in another.
what is performance?
phenotypic value
what is genetic correlation?
strength of relationship between breeding value for one trait and breeding value in another
what are two reasons correlated response exists
gene linkage and pleotrophy
what is environmental correlation?
a measurement of strength of relationships between environmental effects
what is the regression coefficent?
b=((ΣXY)-(ΣX)(ΣY))/n/((Σx^2)-(Σx)^2)/n
what is regression?
expected change in y to x
what are simply inherited traits?
traits that are affected by few genes, such as coat color
environmental factors have ______ effect on traits
little
what are polygenic traits?
traits affected by many genes, such as milk productions.
what do the letters in this equation mean? P= μ+G+E
P- phenotypic value
μ- population mean
G- genotypic value
E- environmental factors
what is genotypic value and how do you find it?
the overall effect of all genes carried in an animal; G=breeding value (BV)+ gene combination value (GCV)
what is breeding value?
genotypic value that can be transmitted from parent to offspring
what is the breeding value equation
the mean of the breeding value of the offspring= the breeding value of the sire+BV of the dom/2
y can not equal _, and cant fall outside the ______ of values.
a; range
what does EPD mean? which animals is it used for?
expected progeny difference. beef, swine, sheep
what does PTA mean? what animals is it used for?
predicted transmission ability. dairy cattle
what are mating systems used for?
it chooses which males are to be bred with which female
what is the goal of selection?
to increase desired alleles
what is inbreeding good for?
making animals more homozygous for superior genes from an ancestor
what is outbreeding good for?
increasing heterozygosity and hybrid vigor
what are the effects of inbreeding?
prepotency expression of deleterious recessive alleles inbreeding depression fixed characteristics concentrates genes increases similar genes
what is the equation of measuring inbreeding?
Fx= Σ1/2^(n1+n2+1)(1+Fca)
what is the equation for genetic relationships?
Rxy= Σ1/2n(1+Fca)/the square root of (1+Fx)(1+Fy)
what is outbreeding
the mating between individuals not closely related genetically, but within the same breed
where is outbreeding used alot?
the poultry industry
what is grading up?
the mating of PUREBLOOD MALES to NONPUREBLOOD females
what is cross breeding?
the crossing of different breeds such as a horse and a donkey
what does synthetic mean?
combination of different lines of ancestry
what is heterosis?
increased heterozygosity
what is the net effect?
influences affecting the trait
what is the equation for % heterosis?
the mean of the offspring + the mean of the parents divided by the mean of the parents all multiplied by 100
what is breed compelation?
combining desired traits in two or more breeds
what are the major uses of outbreeding?
commercial cow/calf, swine, poultry, and sheep
what is limited crossbreeding used for?
dairy, poultry, and wool sheep
what does hybrid vigor increase in dairy cattle
feetility, health, and survivability
what is GCA and what is it used for?
general combination ability; they are used for multiple breeds
what is SCA and what is it used for?
specific combining ability; used for only 2 breeds
what does days open mean?
the window of fertility
what are the systems for cross breeding?
define objectives breeds herd size implementation cost vs. expexted return nothing is free
what are the three major cross breeding systems
terminal, rotational, and rotaterminal
