Twenty sprint cyclists were randomly selected to be in a study designed to test the effectiveness of 12 weeks of creatine supplementation on performance. ten cyclists received a creatine supplement for 3 months while the other ten received a powdered supplement with the same color and texture that has no physical effect for 3 months. the cyclists did not know which supplement they were taking but the researcher did. this study is an example of:

is a blind, neutral experiment

Explanation:

In Science, to have results in which you can trust, always need to be a comparative ( in this case the creatinine supplementation and the other powder). To be a serious experiment, need to have the same activities, duration and the participants need to "blind" to know which substance they are really taking, so they need to train as usual, and after some time the results will show if there is a significant difference.