Dr. Duffy conducted an experiment to raise I.Q. scores by having experimental subjects eat three bananas a day for a month, while control groups had no bananas. Below are his results scores = average I.Q. score for group of subject). $$\begin{array} { l l l }
& \text { Pretest } & \text { Posttest } \
\hline \text { Experimental Group } & 102 & 110 \
\hline \text { Control Group } & 80 & 110
\end{array}$$ Which of the following can you say about the results?
A) The experiment proves that the Dr. Duffy's treatment works.
B) The experiment has a statistical regression issue.
C) The experiment has history effects.
D) The experiment has selection bias problems.

Question

Dr. Duffy conducted an experiment to raise I.Q. scores by having experimental subjects eat three bananas a day for a month, while control groups had no bananas. Below are his results scores = average I.Q. score for group of subject). $$\begin{array} { l l l } 
& \text { Pretest } & \text { Posttest } \
\hline \text { Experimental Group } & 102 & 110 \
\hline \text { Control Group } & 80 & 110
\end{array}$$ Which of the following can you say about the results?
A) The experiment proves that the Dr. Duffy's treatment works.
B) The experiment has a statistical regression issue.
C) The experiment has history effects.
D) The experiment has selection bias problems.

Quizplus · Accepted Answer

The control group started with a significantly lower average I.Q. score (80) compared to the experimental group (102), indicating that the groups were not equivalent at the beginning of the study. This discrepancy suggests that the experiment has selection bias problems, as the initial differences between the groups could account for the observed outcomes rather than the treatment itself.

Dr Duffy Conducted an Experiment to Raise I Which of the Following Can You Say About the Results