In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. The biggest decrease in blood pressure was for those who received the low dosage of the drug. Why should the participants be blinded to which dosage they receive?

It is necessary for the participants to be blinded to which dosage they receive, so as to make the results completely unbiased.

Step-by-step explanation:

It is necessary for the participants to be blinded to which dosage they receive, so as to make the results completely unbiased. If the patients knew the amount of dosage, they might think about it intensively and thus affecting their blood pressure in an abnormal way.

For example, if a patient knows he is given a placebo he will think that his blood pressure is not going to be normal and it will affect his thought process. Thinking about it intensively, will ultimately affect his blood pressure. Thus, the results produced will be biased and will not yield correct conclusion.