Gabriel Multiple Comparison Test and Plot the Confidence Interval on Barplot

Functions for conducting and plotting Gabriel's (1978) multiple comparison test accounting for unequal variance and unequal sample sizes.

Details

This package was created to analyze multi-level one-way experimental designs. It is designed to handle vectorized observation and factor data where there are unequal sample sizes and population variance homogeneity can not be assumed.To conduct the Gabriel test, create two vectors: one for your observations and one for the factor level of each observation. The function, rgabriel, conduct the test and save the output as a vector to input into the gabriel.plot function, which produces a confidence interval plot for Multiple Comparison.

Note

More details on the simulation of studentized maximum modulus's distribution from http://cos.name/cn/topic/142002.

References

Gabriel, K.R., 1978. A Simple Method of Multiple Comparisons of Means. Journal of the American Statistical Association 73, 724.

Stoline, M.R., Ury, H.K., 1979. Tables of the Studentized Maximum Modulus Distribution and an Application to Multiple Comparisons among Means. Technometrics 21, 87.

Author

Yihui XIE <https://yihui.org/> Miao YU <https://yufree.cn/>

Examples



# equal numbers

g <- c(1:50)
f <- c(rep(1,10),rep(2,10),rep(3,10),rep(4,10),rep(5,10))
gabriel.plot(g,f,rgabriel(g,f))


# unequal numbers

g <- c(1:40)
f <- c(rep(1,3),rep(2,12),rep(3,15),rep(4,5),rep(5,5))
gabriel.plot(g,f,rgabriel(g,f))