qanova function

Quantile ANOVA

One-way ANOVA based on quantiles. Only known method to work well when tied values are likely to occur.

Qanova(formula, data, q = 0.5, nboot = 600, ...)

Arguments

• formula: an object of class formula.
• data: an optional data frame for the input data.
• q: quantile (or vector of quantiles) to be used.
• nboot: number of bootstrap samples
• ...: currently ignored.

Details

Test global hypothesis that J independent groups have equal quantiles (default: median) using the Harrell-Davis estimator. Performs well when there are tied values.

Returns

Qanova an object of class "qanova" containing:

• psihat: value of the test statistics

• contrasts: contrasts

• p.value: p-value

• call: function call

References

Wilcox, R. (2012). Introduction to Robust Estimation and Hypothesis Testing (3rd ed.). Elsevier.

See Also

qcomhd, t1way, discANOVA

Examples

## median comparison
set.seed(123)
fitmed <- Qanova(libido ~ dose, viagra, nboot = 200)
fitmed

## 1st, 3rd quartile comparison
set.seed(123)
fitquart <- Qanova(libido ~ dose, viagra, q = c(0.25, 0.75), nboot = 200)
fitquart