An experimenter conducts a study in which she wants to investigate the effects of eating chocolate on concentration.To do this she gives 20 people in an experimental condition a bar of chocolate and gives another 20 people in a control group nothing.However 4 of the people in the experiment withdraw because the dislike chocolate.Which of the following is a threat to internal validity?
A)Regression to the mean.
B)Practice effects.
C)Demand characteristics.
D)Mortality effects.
E)Experimenter bias.

Question

Quizplus · Accepted Answer

The withdrawal of 4 participants from the experimental group due to dislike of chocolate is a threat to internal validity called mortality effects, as it affects the representativeness and comparability of the two groups.

An Experimenter Conducts a Study in Which She Wants to Investigate