@Zen @whuber Zen, please consider undeleting your answer which is a very good one. Perhaps you have been turned off by the OP's tone in his comments, but your answer is nonetheless a useful addition to this site. Perhaps whuber can clean up some of the comments that follow the answer.....

@DilipSarwate I agree it's a good one and I appreciate that @Zen acted on my suggestion to remove the phrases I suspected might be confusing. I hesitate unilaterally to reopen it, though--but if I do discover that he has reopened it, I will be happy to give it an upvote.