Confidence interval for a standardized mean

Source: R/statpsych1.R

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

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)
#>  Estimate adj Estimate        SE        LL       UL
#>  1.232877     1.209015 0.2124335 0.8165146 1.649239

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