# Modified signed-likelihood ratio test (SLRT) for equality of CVs, using summary statistics when raw measurement data are not available.

Modified signed-likelihood ratio test (SLRT) for equality of CVs, using summary statistics when raw measurement data are not available.

mslr_test2(nr, n, x, s, seed)

Arguments

• nr: numeric vector lenght one, number of simulation runs
• n: a numeric vector, the number of observations in each group
• x: a numeric vector, the mean of each group
• s: a numeric vector, the standard deviation of each group
• seed: optional, an integer that is the starting point used in the generation of a sequence of random numbers. Include a seed if you want reproducible output.

Returns

a list with the test statistic and p-value

Examples

# Summary stats from Feltz and Miller 1996

miller <- data.frame(test = c('ELISA', 'WEHI', '`Viral inhibition`'),
                    Mean = c(6.8, 8.5, 6.0),
                    CV =   c(0.090, 0.462, 0.340),
                    N =    c(5, 5, 5))
# compute SD from mean and cv
miller$SD <- with(miller, CV * Mean)

 mslr_test2(nr = 1e3, n = miller$N, s = miller$SD, x = miller$Mean)

References

http://link.springer.com/article/10.1007/s00180-013-0445-2