Please help with one problem

Please see the second half of my original reply, reprinted here for
your convenience:

Failing that, what have you tried? Have you gotten error messages or
otherwise gone wrong? We will help with specific R questions presented
with complete information as described in the posting guide. This isn't
an R question.

In other words, what's your question?

Sarah

Hello Sarah,
Thank you for your post, but this is one task from simpleR book, and I want
to understand the lesson. If you don`t want to help me, OK no problem, but
if anyone can help let do it.

Sarah Goslee
http://www.functionaldiversity.org