How do you calculate the lower bound of a measurement?

To calculate the lower bound of a measurement, subtract half the precision of the measurement from the given value.

When you measure something, the precision of your measurement is determined by the smallest unit you can measure. For example, if you measure a length to the nearest centimetre, the precision is 1 cm. To find the lower bound, you need to consider the possible error in your measurement. This error is half of the precision.

Let's say you have a measurement of 10 cm to the nearest centimetre. The precision here is 1 cm, so half of this precision is 0.5 cm. To find the lower bound, you subtract this half-precision from your measurement: 10 cm - 0.5 cm = 9.5 cm. Therefore, the lower bound of 10 cm measured to the nearest centimetre is 9.5 cm.

This method ensures that you account for the smallest possible value that could have been rounded up to your given measurement. It’s a useful way to understand the range within which the true value of your measurement lies. Remember, the lower bound is always the given measurement minus half the precision, ensuring you never underestimate the possible range of your measurement.