How to determine which measurements cause which?

1. How do you tell which measurement is most accurate?
2. What determines what is to be measured and how?
3. What causes variation in measurements?
4. How do you find the uncertainty of a measurement?

How do you tell which measurement is most accurate?

The smaller the measurement increment, the more precise the tool. Significant figures express the precision of a measuring tool. When multiplying or dividing measured values, the final answer can contain only as many significant figures as the least precise value.

What determines what is to be measured and how?

Determining what to measure is ultimately a question of values and cannot be answered by empirical methods. The decisions about what to measure are determined through social processes.

What causes variation in measurements?

Measurement system variation is all variation associated with a measurement process. Potential sources of variation include gages, standards, procedures, software, environmental components, and so on. Repeatability is the variation due to the measurement device.

How do you find the uncertainty of a measurement?

A common rule of thumb is to take one-half the unit of the last decimal place in a measurement to obtain the uncertainty.