# T&P Terminology Flashcards

- Define accuracy.
- Define error.

**Accuracy**: the closeness of agreement between a measurement and the true value.

**Error**: the difference between a measurement and the true value.

*Accuracy cannot be quantified, whereas error can. True value = that which would have been obtained in an ideal measurement.*

Define precision.

The closeness of agreement between independent measurements obtained under the same conditions.

Define uncertainty.

The interval within which the true value can be considered to lie with a given level of probability.

Give the formula for percentage uncertainty.

100 x uncertainty / measurement

A measuring instrument has increments of magnitude x. What the uncertainty in a single reading?

x/2

A burette has 0.1 cm^{3} increments.

- What is the uncertainty in each measurement?
- To how many decimal places should readings be recorded?

- 0.05 x 2 = 0.1 cm
^{3} - Two decimal places, the second figure being either 0 or 5

*Uncertainty is doubled since you take two readings to get one measurement*