ci.ratio.mad.ps {statpsych}

Confidence interval for a paired-sample MAD ratio

Description

Computes a confidence interval for a ratio of population MADs (mean absolute deviation from median) in a paired-samples design.

Usage

ci.ratio.mad.ps(alpha, y1, y2)

Arguments

alpha

alpha level for 1-alpha confidence

y1

vector of measurement 1 scores

y2

vector of measurement 2 scores (paired with y1)

Value

Returns a 1-row matrix. The columns are:

• MAD1 - estimated MAD for measurement 1

• MAD2 - estimated MAD for measurement 2

• MAD1/MAD2 - estimate of MAD ratio

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

Bonett DG, Seier E (2003). “Statistical inference for a ratio of dispersions using paired samples.” Journal of Educational and Behavioral Statistics, 28(1), 21–30. ISSN 1076-9986, doi:10.3102/10769986028001021.

Examples

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

# Should return:
#     MAD1  MAD2  MAD1/MAD2       LL       UL
# 12.71429   7.5   1.695238 1.109176 2.590961