Hi there! After doing an experiment or test multiple times you will be able to know the accuracy of your tests. If you do the test three times and they all have the same conclusion, it's safe to say that you're results are reliable. However if you do the test 4 times and they are all different then they are most likely unreliable. If this happens you should check your method and retry the experiment/test. Hope this helps, and have a lovely day!!