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Confidence interval for a paired-samples median ratio

Source: R/statpsych1.R
ci.ratio.median.ps.Rd

Computes a distribution-free confidence interval for a ratio of population medians in a paired-samples design. Ratio-scale measurements are assumed. Tied scores within each measurement are assumed to be rare.

For more details, see Section 4.23 of Bonett (2021, Volume 1)

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 for measurement 1

  • Median2 - estimated median for 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. doi:10.3102/1076998620934125 .

Bonett DG (2021). Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.

Examples

y1 = c(76.41, 66.91, 81.06, 74.78, 83.76, 89.31, 78.78, 87.06, 82.61, 76.74, 88.33, 86.18)
y2 = c(59.85, 60.64, 84.86, 68.16, 71.53, 86.18, 67.30, 65.46, 83.50, 66.76, 88.37, 65.02)
ci.ratio.median.ps(.05, y1, y2)
#>  Median1 Median2 Median1/Median2       LL       UL
#>   81.835   67.73        1.208253 1.069251 1.365326

# Should return:
# Median1  Median2  Median1/Median2        LL        UL
#  81.835    67.73         1.208253  1.069251  1.365326