| obtain_inclusion_probabilities {randomizr} | R Documentation |
You can either give obtain_inclusion_probabilities() an declaration, as created by declare_rs or you can specify the other arguments to describe a random sampling procedure.
This function is especially useful when units have different inclusion probabilities and the analyst plans to use inverse-probability weights.
obtain_inclusion_probabilities(declaration = NULL, N = NULL, strata = NULL, clusters = NULL, n = NULL, prob = NULL, strata_n = NULL, strata_prob = NULL, simple = FALSE, check_inputs = TRUE)
declaration |
A random sampling declaration, created by |
N |
The number of units. N must be a positive integer. (required) |
strata |
A vector of length N that indicates which stratum each unit belongs to. |
clusters |
A vector of length N that indicates which cluster each unit belongs to. |
n |
Use for a design in which n units (or clusters) are sampled. In a stratified design, exactly n units in each stratum will be sampled. (optional) |
prob |
Use for a design in which either floor(N*prob) or ceiling(N*prob) units (or clusters) are sampled. The probability of being sampled is exactly prob because with probability 1-prob, floor(N*prob) units (or clusters) will be sampled and with probability prob, ceiling(N*prob) units (or clusters) will be sampled. prob must be a real number between 0 and 1 inclusive. (optional) |
strata_n |
Use for a design in which strata_n describes the number of units to sample within each stratum. |
strata_prob |
Use for a design in which strata_prob describes the probability of being sampled within each stratum. Differs from prob in that the probability of being sampled can vary across strata. |
simple |
logical, defaults to FALSE. If TRUE, simple random sampling is used. When |
check_inputs |
logical. Defaults to TRUE. |
# Draw a stratified random sample
strata <- rep(c("A", "B","C"), times=c(50, 100, 200))
declaration <- declare_rs(strata = strata)
observed_probabilities <-
obtain_inclusion_probabilities(declaration = declaration)
table(strata, observed_probabilities)
# Sometimes it is convenient to skip the declaration step
observed_probabilities <-
obtain_inclusion_probabilities(strata = strata)
table(strata, observed_probabilities)