simple_ra_probabilities: probabilities of assignment: Simple Random Assignment

Description Usage Arguments Value Examples

View source: R/simple_ra.R

Description

probabilities of assignment: Simple Random Assignment

Usage

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simple_ra_probabilities(N, prob = NULL, prob_unit = NULL,
  prob_each = NULL, num_arms = NULL, conditions = NULL,
  check_inputs = TRUE)

Arguments

N

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

prob

Use for a two-arm design. prob is the probability of assignment to treatment and must be a real number between 0 and 1 inclusive and must be length 1. (optional)

prob_unit

Use for a two-arm design. prob is the probability of assignment to treatment and must be a real number between 0 and 1 inclusive and must be length N. (optional)

prob_each

Use for a multi-arm design in which the values of prob_each determine the probabilities of assignment to each treatment condition. prob_each must be a numeric vector giving the probability of assignment to each condition. All entries must be nonnegative real numbers between 0 and 1 inclusive and the total must sum to 1. It may be a conditions-length vector or a N-by-conditions matrix. (optional)

num_arms

The number of treatment arms. If unspecified, num_arms will be determined from the other arguments. (optional)

conditions

A character vector giving the names of the treatment groups. If unspecified, the treatment groups will be named 0 (for control) and 1 (for treatment) in a two-arm trial and T1, T2, T3, in a multi-arm trial. An exception is a two-group design in which num_arms is set to 2, in which case the condition names are T1 and T2, as in a multi-arm trial with two arms. (optional)

check_inputs

logical. Defaults to TRUE.

Value

A matrix of probabilities of assignment

Examples

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# Two Group Designs
prob_mat <- simple_ra_probabilities(N=100)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob=0.5)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each = c(0.3, 0.7),
                        conditions = c("control", "treatment"))
head(prob_mat)

# Multi-arm Designs
prob_mat <- simple_ra_probabilities(N=100, num_arms=3)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each=c(0.3, 0.3, 0.4))
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each=c(0.3, 0.3, 0.4),
                        conditions=c("control", "placebo", "treatment"))
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, conditions=c("control", "placebo", "treatment"))
head(prob_mat)

DeclareDesign/randomizr documentation built on Dec. 7, 2018, 5:10 p.m.