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Confidence interval for a linear contrast of means

Source: R/meta_comp.R
meta.lc.mean1.Rd

Computes the estimate, standard error, and confidence interval for a linear contrast of means from two or more studies. This function will use either an unequal variance (recommended) or an equal variance method. A Satterthwaite adjustment to the degrees of freedom is used with the unequal variance method.

For more details, see Setion 3.2 of Bonett (2021, Volume 5).

Usage

meta.lc.mean1(alpha, m, sd, n, v, eqvar = FALSE)

Arguments

alpha

alpha level for 1-alpha confidence

m

vector of estimated means

sd

vector of estimated standard deviations

n

vector of sample sizes

v

vector of contrast coefficients

eqvar

  • FALSE for unequal variance method

  • TRUE for equal variance method

Value

Returns 1-row matrix with the following columns:

  • Estimate - estimated linear contrast

  • SE - standard error

  • LL - lower limit of the confidence interval

  • UL - upper limit of the confidence interval

  • df - degrees of freedom

References

Bonett DG (2021). Statistical Methods for Psychologists, Vol 1-5, https://dgbonett.sites.ucsc.edu/.

Examples

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)
meta.lc.mean1(.05, m, sd, n, v, eqvar = FALSE)
#>          Estimate       SE        LL        UL    df
#> Contrast    -5.35 1.300136 -7.993588 -2.706412 33.52

# Should return:
#          Estimate       SE        LL        UL    df
# Contrast    -5.35 1.300136 -7.993583 -2.706417 33.52