ci.lc.stdmean.bs {statpsych} | R Documentation |
Computes confidence intervals for a population standardized linear contrast of means in a between-subjects design. The unweighted standardizer is recommended in experimental designs. The weighted standardizer is recommended in nonexperimental designs with simple random sampling. The group 1 standardizer is useful in both experimental and nonexperimental designs. Equality of variances is not assumed.
ci.lc.stdmean.bs(alpha, m, sd, n, v)
alpha |
alpha level for 1-alpha confidence |
m |
vector of estimated group means |
sd |
vector of estimated group standard deviation |
n |
vector of sample sizes |
v |
vector of between-subjects contrast coefficients |
Returns a 3-row matrix. The columns are:
Estimate - bias adjusted standardized linear contrast
SE - standard error
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
Bonett DG (2008). “Confidence intervals for standardized linear contrasts of means.” Psychological Methods, 13(2), 99–109. ISSN 1939-1463, doi: 10.1037/1082-989X.13.2.99.
m <- c(33.5, 37.9, 38.0, 44.1) sd <- c(3.84, 3.84, 3.65, 4.98) n <- c(10,10,10,10) v <- c(.5, .5, -.5, -.5) ci.lc.stdmean.bs(.05, m, sd, n, v) # Should return: # Estimate SE LL UL # Unweighted standardizer: -1.273964 0.3692800 -2.025039 -0.5774878 # Weighted standardizer: -1.273964 0.3514511 -1.990095 -0.6124317 # Group 1 standardizer: -1.273810 0.4849842 -2.343781 -0.4426775