strata_rs implements a random sampling procedure in which units that are grouped into strata defined by covariates are sample using complete random sampling within stratum For example, imagine that 50 of 100 men are sampled and 75 of 200 women are sampled.

## Usage

```
strata_rs(
strata = NULL,
prob = NULL,
prob_unit = NULL,
n = NULL,
n_unit = NULL,
strata_n = NULL,
strata_prob = NULL,
check_inputs = TRUE
)
```

## Arguments

- strata
A vector of length N that indicates which stratum each unit belongs to. Can be a character, factor, or numeric vector. (required)

- prob
Use for a design in which either floor(N_stratum*prob) or ceiling(N_stratum*prob) units are sampled within each stratum. The probability of being sampled is exactly prob because with probability 1-prob, floor(N_stratum*prob) units will be sampled and with probability prob, ceiling(N_stratum*prob) units will be sampled. prob must be a real number between 0 and 1 inclusive. (optional)

- prob_unit
Must of be of length N. tapply(prob_unit, strata, unique) will be passed to

`strata_prob`

.- n
Use for a design in which the scalar n describes the fixed number of units to sample in each stratum. This number does not vary across strata.

- n_unit
Must be of length N. tapply(m_unit, strata, unique) will be passed to

`strata_n`

.- strata_n
Use for a design in which the numeric vector 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.

- check_inputs
logical. Defaults to TRUE.

## Examples

```
strata <- rep(c("A", "B","C"), times = c(50, 100, 200))
Z <- strata_rs(strata = strata)
table(strata, Z)
#> Z
#> strata 0 1
#> A 25 25
#> B 50 50
#> C 100 100
Z <- strata_rs(strata = strata, prob = .3)
table(strata, Z)
#> Z
#> strata 0 1
#> A 35 15
#> B 70 30
#> C 140 60
Z <- strata_rs(strata = strata, n = 20)
table(strata, Z)
#> Z
#> strata 0 1
#> A 30 20
#> B 80 20
#> C 180 20
Z <- strata_rs(strata = strata, strata_prob = c(.1, .2, .3))
table(strata, Z)
#> Z
#> strata 0 1
#> A 45 5
#> B 80 20
#> C 140 60
Z <- strata_rs(strata = strata,
prob_unit = rep(c(.1, .2, .3), times = c(50, 100, 200)))
table(strata, Z)
#> Z
#> strata 0 1
#> A 45 5
#> B 80 20
#> C 140 60
Z <- strata_rs(strata = strata, strata_n = c(20, 30, 40))
table(strata, Z)
#> Z
#> strata 0 1
#> A 30 20
#> B 70 30
#> C 160 40
Z <- strata_rs(strata = strata,
n_unit = rep(c(20, 30, 40), times = c(50, 100, 200)))
table(strata, Z)
#> Z
#> strata 0 1
#> A 30 20
#> B 70 30
#> C 160 40
```