Question38 A researcher wants to study a new drug's effect on mouse behavior. To reduce variability, they decide to use only 8-week-old male mice from a single genetic strain. What is the primary trade-off of this design strategy? The results may not be generalizable to females, other ages, or other strains. It significantly increases the required sample size. It makes randomization of the drug treatment impossible. It introduces confounding by sex and age. It increases the technical variance of the experiment. ResetMaximum marks: 1 Flag question undefined单项选择题
A
The results may not be generalizable to females, other ages, or other strains.
B
It significantly increases the required sample size.
C
It makes randomization of the drug treatment impossible.
D
It introduces confounding by sex and age.
E
It increases the technical variance of the experiment.

Question

Question38 A researcher wants to study a new drug's effect on mouse behavior. To reduce variability, they decide to use only 8-week-old male mice from a single genetic strain. What is the primary trade-off of this design strategy? The results may not be generalizable to females, other ages, or other strains. It significantly increases the required sample size. It makes randomization of the drug treatment impossible. It introduces confounding by sex and age. It increases the technical variance of the experiment. ResetMaximum marks: 1 Flag question undefined单项选择题

A

The results may not be generalizable to females, other ages, or other strains.

B

It significantly increases the required sample size.

C

It makes randomization of the drug treatment impossible.

D

It introduces confounding by sex and age.

E

It increases the technical variance of the experiment.

BlackTom AI · Accepted Answer

Question restatement: A researcher aims to study a new drug's effect on mouse behavior and opts to use only 8-week-old male mice from a single genetic strain to reduce variability. What is the primary trade-off of this design strategy?

Option 1: The results may not be generalizable to females, other ages, or other strains.
- This reflects a classic trade-off in controlled experiments: increasing internal validity by using a homogeneous sample often reduces external validity. By focusing on a single sex, a narrow age, and one strain, the study limits the extent to which findings can be generalized to other populations. This is precisely the expected primary trade-off when standardizing subjects to reduce variability.

Option 2: It significantly increases the required sample size.
- Paring down the population to a narrow group typically reduces between-subject variability, which can actually decrease the needed sample size to detect effects, not increase it. Therefore this option misstates the relationship between homogenization and sample size.

Option 3: It makes randomization of the drug treatment impossible.
- Randomization is about assigning treatments to subjects without bias, and it is independent of subject homogeneity. Selecting a homogeneous group does not inherently prevent randomization; in fact, randomization can still be implemented within that group. This choice confuses population selection with allocation methods.

Option 4: It introduces confounding by sex and age.
- The design choice described reduces, rather than introduces, confounding by sex and age because those variables are held constant across the sample. Confounding would arise if sex or age varied and related to treatment assignment or outcomes; here they are controlled, not confounded.

Option 5: It increases the technical variance of the experiment.
- Reducing biological diversity by using a uniform strain, age, and sex tends to decrease biological variance, not increase it. Technical variance stems from measurement or procedural inconsistencies, which is not directly caused by subject homogeneity across biological characteristics.