A Health Psychology Student Wanted to Know If Giving an Electric

Multiple Choice

A health psychology student wanted to know if giving an electric shock to participants each time they inhale from a cigarette will reduce how deeply they inhale. She arranges for smokers to be randomly assigned to two groups: the first group receives no shock and the second group a painful shock for each puff. Some participants quit the experiment, mostly from the painful- shock group. At the end, there was no difference between the two groups on depth of inhaling. Which of the following is a correct conclusion?

A) electric shock has no effect on depth of inhalation.
B) the study is confounded by differential attrition.
C) the study is confounded by selection bias.
D) the study was confounded by regression artifact.