Significant Digits

Question:

For the lab report that is due on Friday, for the calculations, what is the amount of desired significant figures. I know for one part we were told to use 3, but I just to make sure that 3 is wanted for the entire report. If you can shed any light on this I would appreciate it.

Response:

We’re asking you to identify the number of significant digits in each of your calculations.  Remember that you determine that number from examining the inputs and choosing the input with the least number of significant digits.

We’ll accept an additional digit when performing unit conversions.  For example if converting 181cm to inches we’d accept either 71.3 or 71.26 although the strict interpretation would be only 71.3.

Remember that in conversions you can assume the conversion factor is accurate to as many digits as needed.  e.g.  turning 1 meter into cm you could consider 1 meter = 100.0000000 cm with all those zeros after the decimal point being significant.  Therefore it’s the actual measurement that determines the number of significant digits.

The Wikipedia explanation is pretty good.