Compute power of test or determine parameters to obtain target power.
power.anova.test(groups = NULL, n = NULL,
between.var = NULL, within.var = NULL,
sig.level = 0.05, power = NULL)
Number of groups
Number of observations (per group)
Between group variance
Within group variance
Significance level (Type I error probability)
Power of test (1 minus Type II error probability)
Object of class "power.htest"
, a list of the arguments
(including the computed one) augmented with method
and
note
elements.
Exactly one of the parameters groups
, n
, between.var
,
power
, within.var
, and sig.level
must be passed as NULL,
and that parameter is determined from the others. Notice that
sig.level
has non-NULL default so NULL must be explicitly
passed if you want it computed.
# NOT RUN {
power.anova.test(groups = 4, n = 5, between.var = 1, within.var = 3)
# Power = 0.3535594
power.anova.test(groups = 4, between.var = 1, within.var = 3,
power = .80)
# n = 11.92613
## Assume we have prior knowledge of the group means:
groupmeans <- c(120, 130, 140, 150)
power.anova.test(groups = length(groupmeans),
between.var = var(groupmeans),
within.var = 500, power = .90) # n = 15.18834
# }
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