SEp_from_CIp {metaHelper}

Standard Error from Confidence Interval for Differences of Means

Description

Calculates the standard error from the confidence interval limits for differences of means (and can also be used for the confidence intervals of standardized mean differences, SMD). This method is valid only when the confidence interval is symmetrical around the mean and is applicable for t-distributions or normal distributions (as specified by the t_dist argument). For sample sizes less than 60, it is generally recommended to use the t-distribution.

Usage

SEp_from_CIp(
  CI_low,
  CI_up,
  n1 = NA,
  n2 = NA,
  sig_level = 0.05,
  two_tailed = TRUE,
  t_dist = TRUE
)

Arguments

CI_low

lover OR confidence interval limit

CI_up

upper OR confidence interval limit

n1

sample size group 1 (not required if t_dist = FALSE)

n2

sample size group 2 (not required if t_dist = FALSE)

sig_level

the significance level

two_tailed

whether the two-tailed or one-tailed statistics should be calculated

t_dist

whether the t-distribution should be calculated - requires samples sizes

Value

Pooled standard error (e.g. intervention effect)

References

Cochrane Handbook

Examples

# lower CI = -1.5, upper CI = 0.5
SEp_from_CIp(-1.5, 0.5)