meta.lc.mean1 {vcmeta}

Confidence interval for a linear contrast of means

Description

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.

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

Snedecor GW, Cochran WG (1980). Statistical methods, 7th edition. ISU University Pres, Ames, Iowa.

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)

# Should return:
#          Estimate       SE        LL        UL       df
# Contrast    -5.35 1.300136 -7.993583 -2.706417 33.52169