Confidence interval for an average variance

Source: R/meta_ave.R

Computes the estimate and confidence interval for an average variance from two or more studies. The estimated average variance or the upper confidence limit could be used as a variance planning value in sample size planning.

meta.ave.var(alpha, var, n, bystudy = TRUE)

Arguments

alpha

alpha level for 1-alpha confidence

var

vector of sample variances

n

vector of sample sizes

bystudy

logical to also return each study estimate (TRUE) or not

Value

Returns a matrix. The first row is the average estimate across all studies. If bystudy is TRUE, there is 1 additional row for each study. The matrix has the following columns:

  • Estimate - estimated variance

  • LL - lower limit of the confidence interval

  • UL - upper limit of the confidence interval

Examples

var <- c(26.63, 22.45, 34.12)
n <- c(40, 30, 50)
meta.ave.var(.05, var, n, bystudy = TRUE)
#>         Estimate       LL       UL
#> Average 27.73333 21.45679 35.84589
#> Study 1 26.63000 17.86939 43.90614
#> Study 2 22.45000 14.23923 40.57127
#> Study 3 34.12000 23.80835 52.98319

# Should return:
#         Estimate       LL       UL
# Average 27.73333 21.45679 35.84589
# Study 1 26.63000 17.86939 43.90614
# Study 2 22.45000 14.23923 40.57127
# Study 3 34.12000 23.80835 52.98319