Question

1. corrigan airlines conducted a well - designed experiment using a randomized block design to determine if jet lag disorder could be minimized by varying the internal light levels on trans - atlantic flights. one block was eastbound trans - atlantic flights and one block was westbound trans - atlantic flights. which of the following must be true about the design of this experiment?

a) the number of flights in each block is equal to the number of treatments.
b) the light treatments are randomly assigned to the flights within each block.
c) passengers on eastbound flights are paired with similar passengers on westbound flights.
d) the results of the study are generalizable to flights across the pacific.
e) passengers on eastbound flights receive the light treatment and passengers on westbound flights receive no light treatment.

1. a u.s. air force academy psychologist investigated the effects of different breakfast conditions on the cognitive function of pilots. the pilots, all volunteers, consumed a low carbohydrate or high carbohydrate breakfast drink - randomly assigned - on the first day of the study. after breakfast, the pilots were tested on various flight performance indicators in a flight simulator. after a three - day washout period the pilots were given the other treatment and tested again. which of the following is the best description of the study?

a) an observational study using a simple random sample
b) an observational study using a stratified random sample
c) an observational study using a cluster sample
d) an experiment using a completely randomized design
e) an experiment using a matched - pairs design

Explanation:

• Question 6: In a randomized block design, treatments (in this case, light treatments) are randomly assigned within each block. Option A is incorrect as there's no requirement for the number of flights in each block to equal the number of treatments. Option C is wrong as it's about flight blocks, not passenger pairing. Option D is incorrect because the experiment is about trans - Atlantic flights, not Pacific flights. Option E is wrong as there's no indication of such a treatment assignment (all blocks should have treatment assignments within them).
• Question 7: Each pilot acts as their own pair. First, they receive one treatment (low - carbohydrate or high - carbohydrate breakfast), then after a washout period, they receive the other treatment. This is a matched - pairs design. An observational study would not assign treatments (so A, B, C are wrong). A completely randomized design would not have the same subjects receive both treatments (so D is wrong).

Answer:

• Question 6: B. The light treatments are randomly assigned to the flights within each block.
• Question 7: E. An experiment using a matched - pairs design.