| declare_rs {randomizr} | R Documentation |
Declare a random sampling procedure.
declare_rs(N = NULL, strata = NULL, clusters = NULL, n = NULL, prob = NULL, strata_n = NULL, strata_prob = NULL, simple = FALSE, check_inputs = TRUE)
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. |
A list of class "declaration". The list has five entries: $rs_function, a function that generates random samplings according to the declaration. $rs_type, a string indicating the type of random sampling used $probabilities_vector, A vector length N indicating the probability of being sampled. $strata, the stratification variable. $clusters, the clustering variable.
# The declare_rs function is used in three ways:
# 1. To obtain some basic facts about a sampling procedure:
declaration <- declare_rs(N = 100, n = 30)
declaration
# 2. To draw a random sample:
S <- draw_rs(declaration)
table(S)
# 3. To obtain inclusion probabilities
probs <- obtain_inclusion_probabilities(declaration)
table(probs, S)
# Simple Random Sampling Declarations
declare_rs(N = 100, simple = TRUE)
declare_rs(N = 100, prob = .4, simple = TRUE)
# Complete Random Sampling Declarations
declare_rs(N = 100)
declare_rs(N = 100, n = 30)
# Stratified Random Sampling Declarations
strata <- rep(c("A", "B","C"), times=c(50, 100, 200))
declare_rs(strata = strata)
declare_rs(strata = strata, prob = .5)
# Cluster Random Sampling Declarations
clusters <- rep(letters, times = 1:26)
declare_rs(clusters = clusters)
declare_rs(clusters = clusters, n = 10)
# Stratified and Clustered Random Sampling Declarations
clusters <- rep(letters, times = 1:26)
strata <- rep(NA, length(clusters))
strata[clusters %in% letters[1:5]] <- "stratum_1"
strata[clusters %in% letters[6:10]] <- "stratum_2"
strata[clusters %in% letters[11:15]] <- "stratum_3"
strata[clusters %in% letters[16:20]] <- "stratum_4"
strata[clusters %in% letters[21:26]] <- "stratum_5"
table(strata, clusters)
declare_rs(clusters = clusters, strata = strata)
declare_rs(clusters = clusters, strata = strata, prob = .3)