Question

1. does a mediterranean diet during pregnancy improve child neurodevelopment at age 2 years? a study was conducted involving 1,221 pregnant women. the women were randomly assigned into three groups for four weeks during their pregnancies: a mediterranean diet intervention, a stress reduction program, and usual prenatal care with no interventions. a total of 626 children were assessed at age 2 years and it was determined that children in the mediterranean diet group had higher scores in the cognitive domain and social - emotional domain than in the usual care group.

a. is the study described an observational study or an experiment? explain.
b. based on the results, can the researchers conclude that the eating a mediterranean diet during pregnancy caused higher scores? explain.
c. about half of the mothers who initially participated in the study did not bring their children in for an assessment. explain how this could affect the analysis of the results.

Explanation:

• a. In an experiment, researchers assign participants to different groups (like the Mediterranean - diet group, stress - reduction group, and usual - care group here). Since the women were randomly assigned to these groups, it is an experiment.
• b. Because it is an experiment (with random assignment), we can conclude that the Mediterranean diet during pregnancy (the treatment) caused the higher scores. Random assignment helps control for confounding variables.
• c. If about half of the mothers did not bring their children for assessment, there could be non - response bias. Maybe the mothers who did not bring their children had some characteristics (e.g., more stressed, less likely to follow the diet properly) that could be related to both the non - participation and the outcome (children's scores). This could make the results less generalizable and potentially skew the analysis.

Answer:

• a. It is an experiment. Women were randomly assigned to groups.
• b. Yes. Random assignment in an experiment allows causal conclusion.
• c. Non - response bias. Missing data may be related to outcome and other variables.