パッケージ "ggsignif" をインストールしようとして、
install.packages(ggsignif)と入れて実行したら下記エラーメッセージ↓
Error in library(ggsignif) : there is no package called ‘ggsignif’
なので、下記ページを参照して、
Enrich your ggplots with group-wise comparisons. This package provides an easy way to indicate if two groups are significantly different. Commonly this is shown by a bracket on top connecting the groups of interest which itself is annotated with the level of significance (NS, *, **, ***). The package provides a single layer (geom_signif()) that takes the groups for comparison and the test (t.test(), wilcox.text() etc.) as arguments and adds the annotation to the plot.
install.packages("remotes")
remotes::install_github("const-ae/ggsignif")
と入れたら、無事にインストール → 読み込みできた。
