Sig fig or decimal places for variance?

  • Thread starter ZedCar
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I believe I can summarize this conversation even more concisely.In summary, a set of numbers was given and the variance was calculated to be 0.208. The question arose whether it would be better to report the answer as 0.208 or round it to 0.2. The general consensus is that 0.208 is the better answer according to the rules of significant figures.
  • #1
ZedCar
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Homework Statement



Calculate variance of 34.1, 35.6, 35.8, 34.3, 32.9, 33.7


Homework Equations





The Attempt at a Solution



A set of numbers: 34.1, 35.6, 35.8, 34.3, 32.9, 33.7

I have calculated the variance to be = 0.208

Would it be better to quote to three sig fig as I have done. This being the number of sig fig of the numbers in the set.

Or should I quote it as 0.2, this being the same number of decimal places of the numbers in the set.

Thanks
 
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  • #2
here's a reference to help:

http://www.usca.edu/chemistry/genchem/sigfig2.htm [Broken]

from it I'd conclude that 0.208 is the better answer.
 
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  • #3
Thanks very much for the link jedishrfu
 

What is a significant figure?

A significant figure is a digit in a number that carries meaning contributing to its precision. This includes all digits except leading and trailing zeros.

What is the purpose of using significant figures in scientific calculations?

The use of significant figures ensures that the calculated result is not more precise than the original data used. It also helps to maintain consistency and accuracy in reporting and comparing data.

How do you determine the number of significant figures in a given number?

The general rule for determining significant figures is that all non-zero digits are significant, all leading zeros are not significant, and all trailing zeros are significant if there is a decimal point present.

What is the difference between significant figures and decimal places?

Significant figures represent the precision of a measurement, while decimal places represent the accuracy of a measurement. Significant figures are determined by the original data, while decimal places are determined by the instrument or method used to make the measurement.

What are the rules for rounding when dealing with significant figures?

When rounding to a certain number of significant figures, the general rule is to round up if the first digit dropped is 5 or greater, and round down if the first digit dropped is less than 5.

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