ci.stdmean {statpsych}

Confidence interval for a standardized mean

Description

Computes a confidence interval for a population standardized mean difference from a hypothesized value. If the hypothesized value is set to 0, the reciprocals of the confidence interval endpoints gives a confidence interval for the coefficient of variation (see ci.cv).

ci.stdmean1 is deprecated and will soon be removed from statpsych; please switch to ci.stdmean

Usage

ci.stdmean(alpha, m, sd, n, h)

ci.stdmean1(alpha, m, sd, n, h)

Arguments

alpha

alpha level for 1-alpha confidence

m

estimated mean

sd

estimated standard deviation

n

sample size

h

hypothesized value of mean

Value

Returns a 1-row matrix. The columns are:

• Estimate - estimated standardized mean difference

• adj Estimate - bias adjusted standardized mean difference estimate

• SE - standard error

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

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.

Examples

ci.stdmean(.05, 24.5, 3.65, 40, 20)

# Should return:
# Estimate  adj Estimate        SE        LL       UL
# 1.232877      1.209015 0.2124335 0.8165146 1.649239