sapply(y,function(x) colMeans(x[,c("Ozone","Solar.R","Wind","Temp")]),na.rm=TRUE)
使用缺失值的命令应该属于colmeans里
sapply(y,function(x) colMeans(x[,c("Ozone","Solar.R","Wind","Temp")],na.rm=TRUE))应该这样写
sapply(s, function(x) colMeans(x[,c("Wind", "Ozone", "Temp")],na.rm = TRUE))
少写了一个括号,在最后的部分