complete_rs implements a random sampling procedure in which fixed numbers of units are sampled. The canonical example of complete random sampling is a procedure in which exactly n of N units are sampled.

Users can set the exact number of units to sample with n. Alternatively, users can specify the probability of being sampled with prob and complete_rs will infer the correct number of units to sample. complete_rs will either sample floor(N*prob) or ceiling(N*prob) units, choosing between these two values to ensure that the overall probability of being sampled is exactly prob. Users should specify N and not more than one of n or prob.

If only N is specified, N/2 units will be sampled. If N is odd, either floor(N/2) units or ceiling(N/2) units will be sampled.

## Usage

complete_rs(
N,
n = NULL,
n_unit = NULL,
prob = NULL,
prob_unit = NULL,
check_inputs = TRUE
)

## Arguments

N

The number of units. N must be a positive integer. (required)

n

Use for a design in which exactly n units are sampled. (optional)

n_unit

unique(n_unit) will be passed to n. Must be the same for all units (optional)

prob

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

prob_unit

unique(prob_unit) will be passed to the prob argument and must be the same for all units.

check_inputs

logical. Defaults to TRUE.

## Value

A numeric vector of length N that indicates if a unit is sampled (1) or not (0).

## Examples

S <- complete_rs(N = 100)
table(S)
#> S
#>  0  1
#> 50 50

S <- complete_rs(N = 100, n = 50)
table(S)
#> S
#>  0  1
#> 50 50

S <- complete_rs(N = 100, n_unit = rep(50, 100))
table(S)
#> S
#>  0  1
#> 50 50

S <- complete_rs(N = 100, prob = .111)
table(S)
#> S
#>  0  1
#> 89 11

S <- complete_rs(N = 100, prob_unit = rep(.1, 100))
table(S)
#> S
#>  0  1
#> 90 10

# If N = n, sample with 100% probability...
complete_rs(N=2, n=2)
#> [1] 1 1

# Up through randomizr 0.12.0,
# This behavior has been deprecated
complete_rs(N=1, n=1) # sampled with 50% probability
#> [1] 1