R-描述性统计

RT。。。老实说这一章我是抖的。。。但是，加油～

# 从1:100中均匀抽取size个数据，replace=TRUE指有放回抽样，数据可以重复
x = sample(1:100, size = 100, replace = TRUE)
y = x
# 随机设置y中有20%的缺失值
y[sample(x = 1:100, size = 20, replace = FALSE)] = NA
# 不设置na.rm=TRUE的话，mean会返回NA，哪怕只有一个缺失值
# mean, weighted.mean, var, sd, min, max, median
mean(y, na.rm = TRUE)
# weighted.mean
weighted.mean(x = y, w = y, na.rm = TRUE)
# min, 1st quantile, median, mean, 3rd quantile, max, #NA
summary(y)
# probs设置想要的分位数，要设置na.rm
quantile(y, probs = c(0.25, 0.5, 0.75), na.rm = TRUE)