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Confidence interval for a standardized linear contrast of means in a between-subjects design

Source: R/statpsych1.R
ci.lc.stdmean.bs.Rd

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.

For more details, see Section 3.4 of Bonett (2021, Volume 1)

Usage

ci.lc.stdmean.bs(alpha, m, sd, n, v)

Arguments

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

Value

Returns a 3-row matrix. The columns are:

  • Estimate - estimated standardized linear contrast

  • adj Estimate - bias adjusted standardized linear contrast 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 .

Bonett DG (2021). Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.

Examples

m <- c(6.94, 7.15, 4.60, 3.68)
sd <- c(2.21, 2.83, 2.29, 1.90)
n <- c(40, 40, 40, 40)
v <- c(.5, .5, -.5, -.5)
ci.lc.stdmean.bs(.05, m, sd, n, v)
#>                          Estimate adj Estimate      SE     LL     UL
#> Unweighted standardizer:   1.2459       1.2399 0.17621 0.9005 1.5912
#> Weighted standardizer:     1.2459       1.2399 0.17313 0.9065 1.5852
#> Group 1 standardizer:      1.3145       1.2890 0.22515 0.8732 1.7558

# Should return:
#                          Estimate adj Estimate      SE     LL     UL
# Unweighted standardizer:   1.2459       1.2399 0.17621 0.9005 1.5912 
# Weighted standardizer:     1.2459       1.2399 0.17313 0.9065 1.5852
# Group 1 standardizer:      1.3145       1.2890 0.22515 0.8732 1.7558