J
John Benson
I got the multiplication precision rule wrong:
relative precision is defined as the uncertainty divided by the magnitude of the measured quantity, e.g.
10 meters +/- 1 meter gives an uncertainty of 1 meter, and a relative precision of 1/10 or 10%
The rule is that the relative precision of the multiplication is the sum of the relative precisions of the factors.
When we square 10 +/- 1 meters to find the square area corresponding to that side, we get 100 square meters with a relative precision of
1/10 + 1/10
or a 20% relative precision of the 100 square meter result, which squares (sorry) with the +/- 20 range computed by squaring the range 9 through 11 meters for a squared area range of 81 through 121 square meters.
The problem still remains, though, that the midpoint of the squared range is 101, and not 100!
relative precision is defined as the uncertainty divided by the magnitude of the measured quantity, e.g.
10 meters +/- 1 meter gives an uncertainty of 1 meter, and a relative precision of 1/10 or 10%
The rule is that the relative precision of the multiplication is the sum of the relative precisions of the factors.
When we square 10 +/- 1 meters to find the square area corresponding to that side, we get 100 square meters with a relative precision of
1/10 + 1/10
or a 20% relative precision of the 100 square meter result, which squares (sorry) with the +/- 20 range computed by squaring the range 9 through 11 meters for a squared area range of 81 through 121 square meters.
The problem still remains, though, that the midpoint of the squared range is 101, and not 100!