a large amount of + the plural form of a countable noun?

[ohmyrichard]

Hi, everyone.
Today when I was reading an article on anti-plagiarism software, I came across the structure of "a ... amount of the plural form of a countable noun". The whole paragraph in which the structure appears goes as follows:

"There's an increasing amount of freshmen who don't know how to write a research paper," Sheldon says. "There seems to be a lot of confusion. They're not out to violate, but I do think that there's something going on."

I remember The CoBuild Usage Dictionary tells us not to use "an amount of" with things or people. Last weekend, when I was on a panel of judges for the graduating students' oral defense of their theses, I asked a student to change "a large amount of scholars (in the United States believe that the novel The Sun Also Rises reflects the richness of the content and artistic style of the originality of Hemingway's writing.)" to "a large number of scholars ..." Did I make a big mistake here? Quite probably the student copied the whole sentence from an article written by a native writer and he would laugh at my stupidity in urging him to change what is real English to what sounds unnatural.
I beg you to do me a favour and tell me why this structure goes against authoritative dictionaries. Is this an issue of style? Is it a colloquialism, which is not used in formal writing or speech?
Please help me out.
Thanks.
Richard

[mammamaia]

i'd correct that 'amount' to 'number' if i was editing the piece...

[Cogito]

If you quantify with a count, you would refer to a large number of xxxx/
If you quantify by a continuous measure, meaning rhat a fractional value has meaning, then you would refer to a large amount of xxxx.

Te same thing could be measured in either way. For instance, a beach contains a huge number of sand grains, The amount of sand is many tons.

Split a grain of sand, and you don't have half a grain, you have two grains (split a person and you have no persons). Countable. Split a ton tree ways and you have a third of a ton. Continuous measurement.