when should I use "on average" and when "an average of"?

[mrwroc]

Does "on average" and "an average of" mean the same? Example sentences:

1. Prices have risen by an average of four percent over the past year.

Can I change it to:
On average, prices have risen by four percent over the past year.

2. My income's rather variable, but I earn £175 a day on average.
3. The city's police chief says they arrest, on average, 300 people each day.

Can I change it to:
My income's rather variable, but I earn an average of £175 a day.
The city's police chief says they arrest an average of 300 people each day.

 

[Ryan the Lion]

not a teacher

They do mean the same thing essentially - yes. Both examples also sound natural and conform to standard English rules.
I will just mention that 'an average of' will more likely be heard with numbers and digits, whereas 'average' will be for general use such as "The average wage...", "I'm just average" to list but a couple.

Those sentences are completely correct and almost absolutely interchangeable. My natural instincts tell me there will be exceptions, but they are few and far between and not ones you would encounter.

*Replied via my Mobile

 

[Rover_KE]

Ryan the Lion, please read this extract from the forum's Posting Guidelines:

You are welcome to answer questions posted in the Ask a Teacher forum as long as your suggestions, help, and advice reflect a good understanding of the English language. If you are not a teacher, you will need to state that clearly in your post.

 

[Ryan the Lion]

Yeah, it was a typo and I made that post on my mobile phone which isn't exactly the best ergonomically.

@Rover_KE
I'll add it to my signature. I was a private teacher in the past, however.

 

[mrwroc]

But, was his opinion correct? Can I use "on average" and "an average of" interchangeably? ;-)

 

[Rover_KE]

You can in this context.

 

[Ryan the Lion]

Not to sound like an upstart because I'm new to the forums, but apart from the sentence structure/syntax, I can't think of many contexts where it can't be used interchangeably. As I said, 'an average of' would be typically used for numbers, charts, statistics but not exclusively.

I'm not currently an active English teacher, but I am a native.

It seems that signatures are reserved for VIPs and as I did teach English professional in the days of yore, I'll keep my status as 'Retired English Teacher' as that best reflects my position.

 

[emsr2d2]

It seems that signatures are reserved for VIPs and as I did teach English professional in the days of yore, I'll keep my status as 'Retired English Teacher' as that best reflects my position.

Now that you've had ten public posts approved by moderators, you should find two things:
1. Your posts will no longer automatically go into moderation.
2. You should now be able to create a signature line in your profile settings.

 

[Ryan the Lion]

Now that you've had ten public posts approved by moderators, you should find two things:
1. Your posts will no longer automatically go into moderation.
2. You should now be able to create a signature line in your profile settings.

Hello.

I can now see the ability and add my signature! Ta very much!

 

[jutfrank]

Can I change it to:
On average, prices have risen by four percent over the past year.

No, I don't suggest you do that. The sentence is fine as it is. In the kind of precise register that this sentence is in, an average of + numerical information is the better phrase to use in the register that this kind of precise written English is in. The phrase on average is a very common adverbial phrase that doesn't have to be used with numerical information at all. Your alternative sentence means the same thing, but sounds more suited as something that may be said rather than written.

My income's rather variable, but I earn an average of £175 a day.

Yes, that's okay. The original sentence is very likely to have been written as an example of casual spoken English.

The city's police chief says they arrest an average of 300 people each day.

It's hard to tell whether this sentence is meant to be spoken or written, but probably spoken. Where did you find all these sentences?.

 

[Glizdka]

Not a teacher
------
I'm sorry for diverting from the topic in the original post, but I thought I had to express my opinion regarding adding a "Not a teacher" in Ryan's posts.

The main purpose is to help users distinguish between quality information coming from professional teachers and people like myself who just want to help to the best of their ability. I honestly see no reason to mark retired English teachers' posts as somehow less valid than active English teachers'. Ryan, if what they're saying is true, has taught the language, is a native speaker, and may have greater knowledge and have had more experience in teaching than many currently active teachers. Marking their posts with a "Not a teacher" might send the wrong kind of information to users, putting them on par with people unqualified to answer complicated, grammar-related questions properly. Besides, there are many retired English teachers on this forum who do not add "Not a teacher" in their posts, including some moderators and people who have been on the forum for many years.

I guess you'll have to prove yourself first, buddy. Welcome to the forum. :hi: