TECHNOLOGY OVERVIEW

Bias Analysis (Multiple Equipment)

BIS.Net Team

Bias is an important characteristic of a measuring system. It can be defined as the difference between the reference (‘actual’) value of a part and the measured value. Bias is related to accuracy.

Bias is usually studied one equipment (instrument, device) at a time. However, sometimes there are multiple devices available to the appraiser all the same type and model. It is then important to establish if there are differences in bias amongst the devices. One at a time studies and comparing is an inefficient way of doing so. A better solution is performing an Analysis of Variance (ANOVA) applied to all instruments of the same model.

The ANOVA will determine if there are statistical differences in the average bias as measured on one part, by one appraiser, and the contribution to total measurement variation.

Output consists of a Dartboard, Bias Consistency Chart, a Probability Plot, an Analysis of Variance table, Summary Statistics as shown below.