Description Usage Arguments Value Examples
Use mdes.bird3() to calculate minimum detectable effect size, power.bird3() to calculate statistical power, and cosa.bird3() for bound constrained optimal sample size allocation (BCOSSA).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25  | mdes.bird3(score = NULL, dists = "normal", k1 = -6, k2 = 6,
           order = 1, interaction = FALSE,
           treat.lower = TRUE, cutoff = 0, p = NULL,
           power = .80, alpha = .05, two.tailed = TRUE, df = n3 - g3 - 1,
           rho2, rho3, omega2, omega3, r21 = 0, r2t2 = 0, r2t3 = 0, g3 = 0,
           rate.tp = 1, rate.cc = 0, n1, n2, n3)
power.bird3(score = NULL, dists = "normal", k1 = -6, k2 = 6,
            order = 1, interaction = FALSE,
            treat.lower = TRUE, cutoff = 0, p = NULL,
            es = .25, alpha = .05, two.tailed = TRUE, df = n3 - g3 - 1,
            rho2, rho3, omega2, omega3, r21 = 0, r2t2 = 0, r2t3 = 0, g3 = 0,
            rate.tp = 1, rate.cc = 0, n1, n2, n3)
cosa.bird3(score = NULL, dists = "normal", k1 = -6, k2 = 6, rhots = NULL,
           order = 1, interaction = FALSE,
           treat.lower = TRUE, cutoff = 0, p = NULL,
           cn1 = 0, cn2 = 0, cn3 = 0, cost = NULL,
           n1 = NULL, n2 = NULL, n3 = NULL,
           n0 = c(10, 3, 100), p0 = .499,
           constrain = "power", round = TRUE, max.power = FALSE,
           local.solver = c("LBFGS", "SLSQP"),
           power = .80, es = .25, alpha = .05, two.tailed = TRUE,
           rho2, rho3, omega2, omega3,
           g3 = 0, r21 = 0, r2t2 = 0, r2t3 = 0)
 | 
score | 
 vector or list; an empirical score variable or an object with class 'score' returned from the   | 
dists | 
 character; distribution of the score variable,   | 
k1 | 
 left truncation point for (uncentered) empirical, truncated normal, or uniform distribution. Ignored when   | 
k2 | 
 right truncation point for (uncentered) empirical, truncated normal, or uniform distribution. Ignored when   | 
order | 
 integer >= 0; order of polynomial functional form specification for the score variable.  | 
interaction | 
 logical; if   | 
rhots | 
 obsolote; use   | 
treat.lower | 
 logical; if   | 
cutoff | 
 decision threshold.  | 
p | 
 proportion of level 1 units in the treatment condition.  | 
power | 
 statistical power (1 - β).  | 
es | 
 effect size (Cohen's d).  | 
alpha | 
 probability of type I error (α).  | 
two.tailed | 
 logical;   | 
df | 
 degrees of freedom.  | 
rho2 | 
 proportion of variance in the outcome between level 2 units (unconditional ICC2).  | 
rho3 | 
 proportion of variance in the outcome between level 3 units (unconditional ICC3).  | 
omega2 | 
 ratio of the treatment effect variance between level 2 units to the variance in the outcome between level 2 units.  | 
omega3 | 
 ratio of the treatment effect variance between level 3 units to the variance in the outcome between level 3 units.  | 
g3 | 
 number of covariates at level 3.  | 
r21 | 
 proportion of level 1 variance in the outcome explained by level 1 covariates.  | 
r2t2 | 
 proportion of treatment effect variance between level 2 units explained by level 2 covariates.  | 
r2t3 | 
 proportion of treatment effect variance between level 3 units explained by level 3 covariates.  | 
rate.tp | 
 treatment group participation rate.  | 
rate.cc | 
 control group crossover rate.  | 
n1 | 
 average number of level 1 units per level 2 unit.  | 
n2 | 
 average number of level 2 units (blocks) per level 3 unit.  | 
n3 | 
 number of level 3 units (blocks).  | 
cn1 | 
 marginal costs per level 1 unit in treatment and control conditions (positional), e.g.   | 
cn2 | 
 marginal cost per level 2 unit.  | 
cn3 | 
 marginal cost per level 3 unit.  | 
cost | 
 total cost or budget. Ignored when   | 
p0 | 
 starting value for   | 
n0 | 
 vector of starting values for   | 
constrain | 
 character; constrains one of the   | 
round | 
 logical;   | 
max.power | 
 logical;   | 
local.solver | 
 subset of   | 
parms | 
 list of parameters used in the function.  | 
df | 
 degrees of freedom.  | 
sse | 
 standardized standard error.  | 
cosa | 
 BCOSSA solution.  | 
mdes | 
 minimum detectable effect size and (1 - α)% confidence limits.  | 
power | 
 statistical power (1 - β)  | 
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16  | score.obj <- inspect.score(rnorm(1000),
                           order = 1, interaction = FALSE,
                           cutoff = 0, k1 = -1, k2 = 1)
power.bird3(score.obj,
            es = 0.25, rho2 = .20, rho3 = .10,
            omega2 = .30, omega3 = .30,
            g3 = 0, r2t3 = 0,
            n1 = 20, n2 = 3, n3 = 20)
# minimum required number of level 1 units for each one of the level 2 block
cosa.bird3(score.obj,
           es = 0.25, rho2 = .20, rho3 = .10,
           omega2 = .30, omega3 = .30,
           g3 = 0, r2t3 = 0,
           n1 = NULL, n2 = 3, n3 = 20)
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