ci.ratio.median.ps {statpsych}

Confidence interval for a paired-samples median ratio

Description

Computes a confidence interval for a ratio of population medians in a paired-samples design.

Usage

ci.ratio.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 from measurement 1

• Median2 - estimated median from measurement 2

• Median1/Median2 - estimated ratio of medians

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

Bonett DG, Price RM (2020). “Confidence intervals for ratios of means and medians.” Journal of Educational and Behavioral Statistics, 45(6), 750–770. ISSN 1076-9986, doi:10.3102/1076998620934125.

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.ratio.median.ps(.05, y1, y2)

# Should return:
# Median1  Median2   Median1/Median2        LL        UL
#      13       30         0.4333333 0.3094838 0.6067451