Volunteers for a human performance study were randomly divided into two groups. The first group had their flexibility measured in the morning after a short meditation session while the second group had their flexibility measured in the afternoon with no previous meditation session. The flexibility scores of the two groups were compared.
The study design for this experiment is called a(n):
A. randomized block design
B. matched pairs design
C. completely randomized design
D. simple random sample design
C. completely randomized design
A. randomized block design
The study design described in the question is a randomized block design (option A).
In a randomized block design, participants are divided into blocks based on a specific characteristic or factor that is likely to influence the outcome of the study. In this case, the characteristic or factor is time of day (morning or afternoon).
The participants are then randomly assigned to the different treatment conditions within each block. In this study, one group had their flexibility measured in the morning after a short meditation session (block 1), while the other group had their flexibility measured in the afternoon with no previous meditation session (block 2).
By using blocks, researchers can ensure that any differences in flexibility scores between groups are not due to the time of day alone, as both blocks include participants from both treatment conditions. This design helps to control for confounding factors and increases the validity of the study results.