1
Which design controls for a known source of random variation by grouping similar experimental units before randomization?
2
In a 2×2 factorial experiment, what term describes the effect of each factor averaged over the levels of the other factor?
3
When three treatment conditions are used, how many possible orderings exist for a fully counterbalanced within‑subject design?
4
Which statistical test is appropriate for comparing two levels of a factor in a completely randomized design?
5
In a matched‑pairs design, why is a paired t‑test preferred over an independent‑samples t‑test?
6
What is the primary disadvantage of a completely randomized design when between‑individual variation is high?
7
Which design is most efficient when studying the interaction between two factors each at three levels?
8
In a within‑subject crossover study, what is the purpose of a washout period?
9
When a factor has quantitative levels (e.g., 0, 10, 20 mg/kg), which analysis is most appropriate to assess a linear trend?
10
Which statement best describes the difference between a factor and a level in experimental design?
11
In a randomised block design, why must replication within each block be ensured?
12
What is the main advantage of a within‑subject design over a between‑subjects design?
13
If a researcher expects a large between‑individual variation due to age, which design modification is most appropriate?
14
In a 2×3 factorial experiment, how many total treatment combinations are tested?
15
Which analysis is required to test for an interaction between two factors in a factorial design?
16
When plotting means of a factorial experiment, non‑parallel lines indicate what?
17
What is the key limitation of a matched‑pairs design when the pairing variable is poorly correlated with the outcome?
18
In a crossover within‑subject study, which of the following is NOT a potential source of bias?
19
Why might a researcher prefer a randomised block design over a completely randomised design when dealing with heterogeneous material?
20
When analyzing data from a factorial experiment, what does a significant interaction term imply about the main effects?
