ci.ratio.cv2: Confidence interval for a ratio of coefficients of variation...

In statpsych: Statistical Methods for Psychologists

Confidence interval for a ratio of coefficients of variation in a 2-group design

Description

Computes a confidence interval for a ratio of population coefficients of variation (CV) in a 2-group design. This confidence interval uses the confidence interval for each CV and then uses the MOVER-DL method (see Newcombe, page 138) to obtain a confidence interval for CV1/CV2. The CV assumes ratio-scale scores.

Usage

ci.ratio.cv2(alpha, m1, m2, sd1, sd2, n1, n2)

Arguments

alpha	alpha level for 1-alpha confidence
m1	estimated mean for group 1
m2	estimated mean for group 2
sd1	estimated standard deviation for group 1
sd2	estimated standard deviation for group 2
n1	sample size for group 1
n2	sample size for group 2

Value

Returns a 1-row matrix. The columns are:

• Estimate - estimated ratio of coefficients of variation

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Newcombe2013statpsych

Examples

ci.ratio.cv2(.05, 34.5, 26.1, 4.15, 2.26, 50, 50)

# Should return:
# Estimate       LL       UL
# 1.389188 1.041478 1.854101
 

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