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Computes the standard error for a median

Source: R/meta_se.R
se.median.Rd

Computes the standard error of a median using a confidence interval for the distribution-free interval (see Snedecor & Cochran, 1980), this function computes a Price-Bonett standard error which is known to be very accurate. If any other type of confidence interval is used, this function computes an approximate standard error.

In a 2-group design, this function can be used to compute the standard error of the median in each group. Then the difference in estimated medians in the two groups can be used as the effect size and the standard error of the difference can be set to the square root of the sum of the squared standard errors from each group. Single-group medians or median differences and their standard errors can be used as input in the meta.ave.gen, meta.lc.gen, and and meta.lm.gen functions.

Usage

se.median(alpha, LL, UL, n, type)

Arguments

alpha

alpha value for 1-alpha confidence interval

LL

lower limit of confidence interval

UL

upper limit of confidence interval

n

sample size

type

  • set to 1 for classical confidence interval

  • set to 2 for any other type of confidence interval

Value

Returns the estimated standard error of the sample median

References

Price RM, Bonett DG (2001). “Estimating the variance of the sample median.” Journal of Computation and Simulation, 68(3), 295–305. doi:10.1080/00949650108812071 .

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

Examples

se.median(.05, 47.21, 68.68, 35, 1)
#>        SE
#>  5.252114

# Should return:
#        SE
#  5.252114