Question

Classify each of the hypothetical experiments as double blind, single blind, or unblinded. At least one experimental technique will be used more than once.

Fill the lines with the answer bank

double blind
single blind
unblinded



A) pharmaceutical company claims that their new eye drop formula is more effective at treating glaucoma than the standard one. A group of doctors decide to test the claim, and they ask their patients to choose which type of eye drop they would like to receive. The doctors keep track of the number of patients prescribed each formula that go blind within five years. __________



B)A baker wants to test if his customers can taste the difference between his regular and his gluten‑free chocolate cupcakes. He gives both cupcakes to each of 100 customers, randomly varying which type of cupcake is presented on the left. After tasting both cupcakes, he asks each customer which cupcake is gluten‑free.______



C)A marketing researcher hires three different artists to design a new animal spokesperson for his company. The researcher has a favorite but wants to determine which will be most beloved by the American public. He sends out an anonymous online survey with pictures of the three animal spokespersons to 10,000 randomly selected people. In each survey, the position of the animal spokespersons on the screen is randomized._________



D)A researcher designs a clinical trial to test if a new medication is effective at reducing cholesterol levels. Each participant in the trial is assigned a random number. Each number is associated with receiving either the medication or a placebo, both of which look and taste identical. The researcher does not have any direct contact with the participants.__________



E)A psychologist wants to test whether the scent of lavender or sandalwood is more effective at getting children to fall asleep. She creates 500 vials of lavender aromatherapy oil and sandalwood oil. The vials are visually indistinguishable. She assigns one vial at random to each of 1000 parents, and they administer the treatment. She monitors the children's sleep patterns from image‑only videos and then asks the parents which type of vial they received._____________

Answer 1

The hypothetical experiments are classified based on the level of blinding: A) unblinded, B) single blind, C) and D) double blind, and E) single blind. Double blind experiments are highly rigorous, controlling for biases and ensuring the integrity of the results.

Step-by-step explanation:

The classification of each hypothetical experiment can be discerned based on the level of blinding involved in the study

• A) This would be an unblinded experiment, as both the doctors and the patients are aware of which eye drop formula is being used.
• B) As the baker knows which cupcakes are gluten-free but the customers do not, this is a single blind experiment.
• C) If the marketing researcher does not know which design has been chosen by the respondents, and the respondents are not influenced by the researcher's preference since the survey is anonymous, this would be a double blind setup.
• D) As neither the participants nor the researcher knows who is receiving the actual medication or the placebo, this is a double blind clinical trial.
• E) This is a single blind study because the psychologist knows which vial contains which scent, but the parents and children do not.

Double blind experiments are considered more rigorous because they control for both experimenter and participant expectations, avoiding biases such as the placebo effect. In the context of clinical trials and scientific experiments, the use of placebos and the random assignment of subjects are critical design elements that help eliminate the influence of lurking variables and ensure the integrity of the results.