Unfortunately delkal, people are arguing from a position lacking knowledge and I have to wonder what agenda they have?
Sighted Test: The subjective evaluator 100% knows that they are evaluating.
Single Blind Test: (This is a blind test). The subjective evaluator has no direct knowledge of what is being tested. The tester may accidentally or on purpose give clues to the subjective evaluator. This test method is used where the potential for bias is low, or the expectation of bias is low by those viewing the results. This is used day in / day out in scientific testing as most of the time, there is no desire to introduce bias and the results are not life/money critical. For that reason, having your friend administer the test for cables, would be suitable assuming they have no skin in the game for the outcome. Similarly, having a supplier administer it would be a no-no as the potential for bias is too high, and the results would be questioned due to that potential for bias.
Double Blind: Neither the subjective evaluator nor the person administering the test knows what is being tested, therefore there is no way for clues to be passed to the subjective evaluator. The almost gold standard of subjective evaluation.
Triple Blind: In addition to the double blind, all test data is coded so that results cannot be linked to a particular item under test during the data processing and analysis stage.
... and again, if you are only proving or disproving a single narrow claim, you don't need multiple subjects nor a complex protocol.
Sighted Test: The subjective evaluator 100% knows that they are evaluating.
Single Blind Test: (This is a blind test). The subjective evaluator has no direct knowledge of what is being tested. The tester may accidentally or on purpose give clues to the subjective evaluator. This test method is used where the potential for bias is low, or the expectation of bias is low by those viewing the results. This is used day in / day out in scientific testing as most of the time, there is no desire to introduce bias and the results are not life/money critical. For that reason, having your friend administer the test for cables, would be suitable assuming they have no skin in the game for the outcome. Similarly, having a supplier administer it would be a no-no as the potential for bias is too high, and the results would be questioned due to that potential for bias.
Double Blind: Neither the subjective evaluator nor the person administering the test knows what is being tested, therefore there is no way for clues to be passed to the subjective evaluator. The almost gold standard of subjective evaluation.
Triple Blind: In addition to the double blind, all test data is coded so that results cannot be linked to a particular item under test during the data processing and analysis stage.
... and again, if you are only proving or disproving a single narrow claim, you don't need multiple subjects nor a complex protocol.