The Same Lab Is Conducting a Longitudinal Study with Assessments

Multiple Choice

The same lab is conducting a longitudinal study with assessments at 6, 18, and 30 months. The study goal is to follow a total of 50 infants over the time period. However, when checking the study log you find that already 60 infants were assessed at age 6 months. The graduate student tells you that more infants were recruited because of:

A) Expected attrition.
B) Unbiased sampling.
C) Normal distribution.
D) All of the above.