摘要： Ex1: Examine the orchis2 data object. Here you see a two-column data frame with a responsevariable (flower) and a predictor variable (site). Produce a histogram for the sprayed site.Now overlay a density plot.1 ggplot(df, aes(x=value)) + geom_histogram(binwidth=.8, colour="black", fill=&qu 阅读全文