a great deal (when it is used about a countable noun)

[Sweetboat]

You cannnot seat them all behind desks in a classroom, dictate information to them and expect them to absorb all of it like a sponge.
Some will do well learning in this way. A great deal will not. (source)

I wonder why the author used 'a great deal' above.
As far as I know you cannot use 'a great deal' about a countable noun, so shouldn't it be 'a great number' instead?

Like this:
Some (students) will do well learning in this way. A great number (of students) will not.

 

[ewie]

Well spotted, Sweetboat
He could/should have said a great number or simply a great many.

 

[velisarius]

Well done, Sweetboat. I read a couple of pages and noticed a few other errors and oddities.

 

[Sweetboat]

Thank you very much, ewie and velisarius.
The author's name is Will Stanton, which sounds like a native speaker of English.
Even a native speaker would make such a mistake?

 

[velisarius]

He says he's Australian. The book seems to be self-published.

 

[PaulQ]

Would even a native speaker would make such a mistake?

I suspect that, in any language, nobody makes no mistakes - it's the amount of mistakes that count.

 

[ewie]

Or even the number of mistakes

 

[Mnemon]

Correct the register errors in the following sentences. There may be more than one.
[4] The government needs to create heaps of jobs to solve this problem.

Common Mistakes at IELTS book
Book's answer: ... create a great deal or a large number of jobs ...

Would it be correct to say "a great deal of jobs"?

 

[ewie]

No it wouldn't. A great deal should be followed by an uncountable noun: a great deal of work, a great deal of patience, etc.

It's a mistake that some people make ... including the authors of your book