Type | Symbol | Definition/description | Units |
---|---|---|---|
Random variables, observed values | Λ, λ | Per host net egg output | eggs gram^{-1} |
W, w | Per host mean weight of female Ascaris | grams | |
n | Per host female worm burden | worms host^{-1} | |
a | Host age group (a = 0 for age ≤ 12, a = 1 for age > 12,) | ||
Unobserved random variables | M | Per host unobserved true mean weight of female Ascaris | grams |
Unobserved values | μ _{ W } | Expected value of the per host mean weight of female Ascaris | grams |
μ _{Λ} | Expected value of the per host net egg output | eggs gram^{-1} | |
p | The probability of observing a zero count from the Bernoulli process | - | |
Estimated parameters | ${\alpha}_{a}=\{{\alpha}_{1a},{\alpha}_{2a},{\alpha}_{3a}\}$ |
Describe the form of density-dependence of the expected value of the per host mean weight of female Ascaris in age group a | - |
$\sigma =\{{\sigma}_{1}^{2},{\sigma}_{2}^{2}\}$ |
Describe the relationship between the variance of the per host mean weight of female Ascaris and the female worm burden | - | |
λ _{1} |
Exponential of the intercept term of statistical models fitting the expected value of the per host net egg output to data | - | |
β |
Describes the effect of host age category on the expected value of the per host net egg output | - | |
c |
An inverse measure of the severity of density dependence (0 <c ≤ 1) on the expected value of the per host net egg output | - | |
$\gamma =\{{\gamma}_{1},{\gamma}_{2},{\gamma}_{3}\}$ |
Describe the form of the relationship between the expected value of the per host net egg output and female Ascaris mean weight | - | |
$\delta =\{{\delta}_{0},{\delta}_{1},{\delta}_{2},{\delta}_{3}\}$ |
Describe the age-dependent relationship between the logit of the probability of observing a zero egg count, the natural logarithm of female worm burden and the natural logarithm of the mean weight of female Ascaris | - | |
k | Inverse measure of the degree of overdispersion in egg output data | - |