Question

A number of samples are used to make an estimate at an unknown location by means of a weighted average. Briefly discuss which possible circumstances might lead to equal weights being assigned to all of the samples. List and briefly explain the two main sources of uncertainty. Briefly explain why it is important to provide a measure of uncertainty with an estimate

Answer 1

A bmw company hires new workers in the garage in order to increase production. The workers want to know the diameter of the tyre of the car to begin with. So 20 sample of bmw cars are chosen and the diameter of the tyres are measured. So as an estimate, we can give the average diameter of the samples (note that, the samples have equal weights in this case).

1. Repeatability : Repeatability is used to see how much variability is in your measurement results under repeatable conditions. i.e there can be measurement errors which causes this type of uncertainty. So measurements should be repeated for a number of samples.
2. Stability : Stability is a random uncertainty. Essentially, stability determines how stable an estimate is over time i.e how well the tyre with the same diameter works after long time.

Quantitative measurements are performed each day. The accuracy of these measurements is determinate upon an established set of requirements. One organization may require low accuracy measurements while another may require high accuracy. Despite the established requirements, no measurement is exact. No matter how careful or accurate, every measurement result contains an independent amount of uncertainty. It is an important aspect of measurement that affects quality, costs, decisions, and risks. The need for increased accuracy is not as important as the need to measure quality. Therefore, if measurement is important, then measurement uncertainty is equally important.