Precision of a measurement

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kim09

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Aug 26, 2006
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The directions are Find the precision for each measurement.

The measurement is 2 1/2 yd.

I think I might know what it is. I'm thinking 2-3 yd, but I'm not really sure because on the other measurements is inches, milimeters, and centimeters. This one kind of confused me too.
 
If the measurement is only accurate to within three yards, then the measurment of "2.5 yards" is meaningless, since it is smaller than the error range.

Please reply with your book's definition of the precision of a measurement. If it lists any formulas, please include those as well.

Thank you.

Eliz.
 
The precision of any measurement depends on the smalles unit available on the measuring tool. The measurement should be precise to withing 0.5 unit of measure. For example, 3 centimeters means that he actual lenght is no less than 2.5 centimeters and no more than 3.5 centimeters. That's what it says in the book about precision, there's more, but I don't think it is necessary to write all of it.
 
If the precision depends upon the unit of measure for the tool, then we need to know the tool used to make the "2.5 yard" measurement, and its unit of measure. (Yards? Feet? Inches?)

Please reply with that information. Thank you.

Eliz.
 
kim09 said:
I think it's yards. I think that's what your asking.
Click to expand...
I am asking for the unit of measurement that is marked on the tool used to obtain the "2.5 yards" measurement. Are you saying that the book gives this as being a stick one yard long, with no markings...?

Eliz.
 
Oh, I got it now. No, it just has 2.5 yd. It's from a paper instead of a book. It's something like assignments from the book though. It just says to find the precision of the measurements.
 
Since the definition of precision requires that we know the measuring unit of the measuring tool, if this unit is not given, then I don't see how you're supposed to arrive at an answer.

I mean, if you'd guessed "2.5 yards" from a yardstick with only one-foot markings on it, then the accuracy would, by the definition, be plus or minus half a foot. But if the yardstick is a fairly standard one, having markings down to the quarter- or eighth-inch, then the accuracy would be plus or minus 1/8" or 1/16".

Without the information required by the definition, the question cannot be answered, as near as I can tell. Sorry.

Eliz.
 
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