Is there a difference between mean speed and average speed ?

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Discussion Overview

The discussion centers on the potential differences between "mean speed" and "average speed," exploring definitions and usage in various contexts. Participants examine whether these terms are interchangeable or if they imply distinct concepts, particularly in relation to specific conditions like uniform acceleration.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that "mean speed" and "average speed" are the same, suggesting that the terms are interchangeable.
  • Others propose that "mean" may refer specifically to a calculation involving initial and final velocities, such as (v+u)/2, while "average speed" is defined as total distance divided by time.
  • A few participants mention the concept of "median" as a different measure, which is particularly relevant in statistics for discrete samples.
  • There is a suggestion that the usage of "mean" versus "average" may vary by region, with some indicating that British English tends to use "mean" while American English prefers "average."
  • One participant questions the validity of the definition of "mean velocity," suggesting it may only apply under specific conditions like uniform acceleration.
  • Another participant notes that the terms have been used interchangeably without much thought, indicating a lack of consensus on their distinct meanings.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether "mean speed" and "average speed" are identical or distinct concepts. Multiple competing views remain, particularly regarding definitions and contextual usage.

Contextual Notes

Some definitions and assumptions about the terms may depend on specific conditions, such as uniform acceleration, which are not universally agreed upon. The discussion also highlights potential ambiguities in language usage across different regions.

mahela007
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Is there a difference between "mean speed " and "average speed"?

Is there a difference between mean speed and average speed? The words "mean" and "average" seem to mean the same thing.
 
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You may be thinking of "median" which is different. Assuming a "sample" rate based on time, over some fixed time interval, it would be the speed at which 1/2 the time in the interval was spent below or at the speed and the other have above or at the speed. Median is more useful in statitics where the samples are discrete and not continuous.
 


Jeff Reid said:
You may be thinking of "median" which is different. Assuming a "sample" rate based on time, over some fixed time interval, it would be the speed at which 1/2 the time in the interval was spent below or at the speed and the other have above or at the speed. Median is more useful in statitics where the samples are discrete and not continuous.

That seems to be the case.
I was told that mean speed is (v+u)/2 (v is final velocity and u is initial)
while average speed is simply distance/time
 


mahela007 said:
That seems to be the case.
I was told that mean speed is (v+u)/2 (v is final velocity and u is initial)
while average speed is simply distance/time

That's correct, but there's no distinction to be made between mean and average. I thought mean is chiefly used in British, and average in American English.
 


Thats some good observation on your part, I never noticed that Americans tend to use avg. and Brits use mean. I just read avg and mean as one and the same.

I suppose its technically less ambiguous to use mean. in reality everyone knows what you are on about anyway

"Take the average speed"
"Erm which average? mean median or mode"
 


Er... hello?

If "mean velocity" is defined as (v+u)/2, while average velocity is the total distanced traveled over time, then they are NOT identical, and it is no longer simply "Americans versus British" usage!

The definition of "mean velocity" is very strange, unless it is for a very specific situation of a uniform, constant acceleration. I would tend to go with Russ and say that they are the same thing, and that this "definition" here needs to be looked at more carefully to see if it is valid.

Zz.
 


ZapperZ said:
Er... hello?

If "mean velocity" is defined as (v+u)/2, while average velocity is the total distanced traveled over time, then they are NOT identical.
I don't think they are... but I'm not a native speaker so I might be wrong. In my language we use the same word for both.
 


mahela007 said:
I was told that mean speed is (v+u)/2 (v is final velocity and u is initial) while average speed is simply distance/time
The "mean" usage is probably assuming constant acceleration, and in that case it's equal to distance over time.

There's also "mean" as in "mean value theorem", where the mean point is the point at which the tangent to the curve has the same slope as the slope from start point to end point. In the case of constant acceleration, velocity versus time is a straight line, and the mean value could be any point on the line, so it doesn't mean much in that case (I know bad pun).
 
  • #10


ZapperZ said:
The definition of "mean velocity" is very strange, unless it is for a very specific situation of a uniform, constant acceleration. I would tend to go with Russ and say that they are the same thing, and that this "definition" here needs to be looked at more carefully to see if it is valid.

Zz.
Good point. I've always used them interchangably without a second thought about the situation.
 

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