r 语言绘图函数

tony_jin2010

写一个函数，计算数据集中每五个观测值的平均值和范围？
如果在数量上的最后一组值的数目小于5，它需要给出的注释它。
例如：

For example if the data are 3,4,5,6,7,2,3,4,5,6,6,1

The function should return:

The average and range of (3,4,5,6,7)

and average and range of (2,3,4,5,6)

and average and range for (6,1) and

a message that in the last group you have only 2 values.

求各位高手指点迷经。

谢谢