Why are samples coded during triangulation tests?

Samples are coded during triangulation tests primarily to reduce expectation errors and habitual scoring. When testers are aware of which sample corresponds to which product, their perceptions and judgments can be influenced by preconceived notions or biases. By coding the samples, it ensures that the participants evaluate them without any prior assumptions about what they're tasting. This method helps to create a more objective assessment of the samples, focusing solely on the sensory characteristics without the influence of branding or other identifiable factors.

This approach is vital in sensory testing to maintain the integrity of the results, allowing for a more accurate comparison between the samples presented. In contrast, the other options do not align with the purpose of sample coding in this context.