Question

In an interesting experiment, researchers examined the effect of ultrasound on birth weight. Pregnant women participating in the study were randomly assigned to one of two groups. The first group of women received an ultrasound; the second group did not. When the subjects’ babies were born, their birth weights were recorded. The women who received the ultrasounds had heavier babies.

Was the experiment double-blind? Why is this important?

Short answer

No.

Step-by-step solution

Given information 

Pregnant women participating in the study were randomly assigned to one of two groups.

Concept

In a double-blind experiment, neither the subjects nor the people who interact with them and assess the response variable are aware of the treatment they received.

Explanation

It wasn't double-blind because neither the subjects nor the researchers knew who had completed the study. Physicians were aware of this. It is critical to eliminate any bias.