ci.sm {MBESS}R Documentation

Confidence Interval for the Standardized Mean

Description

Function to obtain the exact confidence interval for the standardized mean.

Usage


ci.sm(sm = NULL, Mean = NULL, SD = NULL, ncp = NULL, N = NULL, conf.level = 0.95,
 alpha.lower = NULL, alpha.upper = NULL, ...)

Arguments

sm standardized mean
Mean mean
SD standard deviation
ncp noncentral parameter
N sample size
conf.level confidence interval coverage (i.e., 1 - Type I error rate); default is .95
alpha.lower Type I error for the lower confidence limit
alpha.upper Type I error for the upper confidence limit
... allows one to potentially include parameter values for inner functions

Details

The user must specify the standardized mean in one and only one of the three ways: a) mean and standard deviation ('Mean' and 'SD'), b) standardized mean ('sm'), and c) noncentral parameter ('ncp'). The confidence level must be specified in one of following two ways: using confidence interval coverage ('conf.level'), or lower and upper confidence limits ('alpha.lower' and 'alpha.upper').

This function uses the exact confidence interval method based on noncentral t distribution. The confidence interval for noncentral t parameter can be abtained from function 'conf.limits.nct' in MBESS.

Value

Lower.Conf.Limit.Standardized.Mean lower confidence limit of the standardized mean
Standardized.Mean standardized mean
Upper.Conf.Limit.Standardized.Mean upper confidence limit of the standardized mean

Note

The standardized mean is the mean divided by the standard deviation.

Author(s)

Ken Kelley (Indiana University;<KKIII@Indiana.Edu>)

References

Kelley, K. (2006). Constructing confidence intervals for standardized effect sizes: Theory, application, and implementation. Manuscript submitted for publication.

See Also

'conf.limits.nct'

Examples

ci.sm(sm=2.037905, N=13, conf.level=.95)
ci.sm(Mean=30, SD=14.721, N=13, conf.level=.95)
ci.sm(ncp=7.347771, N=13, conf.level=.95)
ci.sm(sm=2.037905, N=13, alpha.lower=.05, alpha.upper=0)
ci.sm(Mean=50, SD=10, N=25, conf.level=.95)

[Package MBESS version 0.0.9 Index]