Rのクラスカル＝ウォリス検定でエラー”all group levels must be finite”

正規分布ではない多群について検定するために krsukal-wallis test を行ったところ、表題のエラーが出た

> kruskal.test(value~label)
Error in kruskal.test.default(c(0.55, 0.62, 0.58, 0.51, 0.5, 0.6, 0.58,  : 
  all group levels must be finite

ここで公式ドキュメントを眺めてみると

kruskal.test(x, g, …)
x : a numeric vector of data values, or a list of numeric data vectors. Non-numeric elements of a list will be coerced, with a warning.
g : a vector or factor object giving the group for the corresponding elements of x. Ignored with a warning if x is a list.
https://www.rdocumentation.org/packages/stats/versions/3.6.1/topics/kruskal.test

どうやら factor を引数に取るらしい

> value <- as.factor(value)

> label <- as.factor(label)

> kruskal.test(value~label)

	Kruskal-Wallis rank sum test

data:  value by label
Kruskal-Wallis chi-squared = 8.1137, df = 3, p-value = 0.04372

これで解決

参考

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