Pet peeve: "expectancy" means "average". It's just "life expectancy" not "average life expectancy"

[Recursion]

You may now go about your business.

[NYC_SKP]

1. An exception. Comparing life expectancy of men in three states, for example,

might be a case where one could reasonably and correctly say, "for these three states, the average life expectancy for men is 77.2 years".

No?

[Recursion]

2. Not in a meaningful way

An expectancy, like any average, is actually the result of an integral (though we use a familiar arithmetic-based shortcut for discrete populations); you can't just take that and put it in another vector and perform another expectancy (well, I mean, there's no Math Police that will stop you, more's the pity, but what you're doing doesn't really mean anything ... which is not to say I haven't seen social scientists do this in papers, and died a little inside).

[pinboy3niner]

3. You can repeat that again!

[Jim Lane]

4. What about this one....

I agree with you in general but there might be exceptions.

"The average life expectancy for a man Abner's age is 28 years, but Abner's life expectancy is 7 years in light of his recent diagnosis."

I'd be inclined to accept that wording because the whole purpose of the sentence is to present the difference between the life expectancy for the whole group and the life expectancy for this individual. Use of "average" serves to highlight that point.

[NightWatcher]

5. I hate people who call the ATM (automated teller machine) the ATM Machine

It's the same with PIN (personal identification number) calling it a PIN number. They've actually just called it the personal identification number number.

[malthaussen]

6. RPM per minute.

I once explained to a lady friend that when she said "RPM per minute" she was describing acceleration, not speed.

She slugged me.

-- Mal