This function plots statistical power curves (for main, moderation, and/or mediation effects) under a fixed budget across optimal design parameters.
# S3 method for power
plot(
expr = NULL,
nlim = c(2, 300),
plim = c(0.01, 0.99),
Jlim = c(3, 300),
powerlim = c(0, 1),
plot.title = NULL,
m = NULL,
d = NULL,
power = 0.8,
q = NULL,
by = c("n", "p", "J"),
legend = TRUE,
nlab = "Level-One Sample Size (n)",
plab = "Proportion (p)",
Jlab = "Level-Two Sample Size (J)",
powerlab = "Statistical Power"
)Returned objects from an od function (e.g., od.2m, od.2m.mod).
The plot range for n, default value is c(2, 50).
The plot range for p, default value is c(0, 1).
The range for solving the root of level-2 sample size
(J) numerically. Change the default values to a larger range
(e.g., starting with a smaller value) if
f() values at end points are not of opposite sign. For example,
use Jlim = c(1.5, 1e10).
The limit for plotting power curves.
The title of the plot (e.g., plot.title = "Power Curves"). The default is NULL.
Total budget, default is the total costs of sampling 60 sites.
Standardized effect size, default is 0.1.
Statistical power.
The number of covariates at level 2. Default is 1.
Dimensions to plot power curves by the optimal design parameters. The default value is by all optimal design parameters for a type of design. For example, default values are by = "p" for single-level designs, by = c("n", "p") for two-level designs, and by = c("n", "p", "J") for three-level designs.
Logical; present plot legend if TRUE. The default is TRUE.
Label for the x-axis when the plot is by the optimal design parameter "n".
Label for the x-axis when the plot is by the optimal design parameter "p".
Label for the x-axis when the plot is by the optimal design parameter "J".
The label for the statistical power.