ci.median.ps: Confidence interval for a paired-samples median difference

In statpsych: Statistical Methods for Psychologists

Confidence interval for a paired-samples median difference

Description

Computes a distribution-free confidence interval for a difference of population medians in a paired-samples design. This function also computes the standard error of each median and the covariance between the two estimated medians.

Usage

ci.median.ps(alpha, y1, y2)

Arguments

alpha	alpha level for 1-alpha confidence
y1	vector of scores for measurement 1
y2	vector of scores for measurement 2 (paired with y1)

Value

Returns a 1-row matrix. The columns are:

• Median1 - estimated median for measurement 1

• Median2 - estimated median for measurement 2

• Median1-Median2 - estimated difference of medians

• SE1 - standard error of median 1

• SE2 - standard error of median 2

• COV - covariance of the two estimated medians

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Bonett2020statpsych

Examples

y1 <- c(21, 4, 9, 12, 35, 18, 10, 22, 24, 1, 6, 8, 13, 16, 19)
y2 <- c(67, 28, 30, 28, 52, 40, 25, 37, 44, 10, 14, 20, 28, 40, 51)
ci.median.ps(.05, y1, y2)

# Should return:
# Median1 Median2 Median1-Median2       SE        LL        UL  
#      13      30             -17 3.362289 -23.58996 -10.41004 
#      SE1      SE2      COV
# 3.085608 4.509735 9.276849

statpsych documentation built on Sept. 11, 2024, 7:42 p.m.