Unit B: Measurement

Degree of Accuracy

When an object is measured, the tool that is used will never produce an exact measurement. The accuracy of a measurement tool is determined by how close a result comes to the true value. Accuracy improves with tools that are calibrated correctly. Measuring tools, such as callipers and scales, must be calibrated regularly by comparing them to a standard to ensure accuracy.

Is it important for all measurements to be accurate? Accuracy is necessary in certain situations; however, estimations would be suitable in some circumstances.

Example 4

Anika compared prices of bathroom scales at a medical supply store. One scale costs $30 and is precise to the nearest 500 g. The second scale costs $120 and is precise to the nearest 100 g. Both scales have been calibrated. Anika would like to purchase the scale for use at her pediatric clinic. Which scale would be more suitable to buy?

Solution

To ensure proper development of children, it is important to have an accurate weight. The scale that costs $120 would produce a weight that is closer to the actual weight of the child. Since the scale is calibrated, it can measure smaller increments. Anika should by the $120 scale for her pediatric clinic.