Question

2. An experiment is to be conducted using a crossover design. The statistician informs the investigator that a rest period, or washout period, should be included in the study plan. The purpose of the rest period is to eliminate or reduce (1 mark)

1. Observer data
2. Missing data
3. Residual treatment effects
4. Problems with patient compliance
5. Adverse drug experiences

Answer 1

Problem statement: To understand why a rest or washout period is required during crossover design.

Given: experiment design chosen for the statistical study is crossover design.

Solution: Answer is option C.

Explanation :Crossover design in statistical study refers to a condition where subjects (samples) are subjected to different "treatments" at different intervals of time. Since a given subject (sample) is exposed to multiple treatments at various instances of time during the experimental study, we need to be wary that a particular effect exhibited by the subject during the study is due to the latest "treatment" administered to the subject and not due to previous treatment.

By including rest period or washout period, the subject (sample) is given sufficient time to recover from the previous "treatment" and is ready to get new "treatment" administered so that any effect exhibited by the subject could be attributed to the latest treatment. Hence, rest period or washout period is used to remove or reduce Residual treatment effects. (Option C)