为进一步探寻引起学习效率下降的原因,我们对实验组和参照组进行了对比研究

为进一步探寻引起学习效率下降的原因,我们对实验组和参照组进行了对比研究 A: Inordertolookintothereasonforthedecreaseoflearningefficiency,weconductedacomparativestudybetweentheexperimentalgroupandthecontrolgroup. B: Inordertoinvestigatethereasonforthedecreaseoflearningefficiency,acomparativestudywasconductedbetweentheexperimentalgroupandthecontrolgroup.

The biggest difference between Observational studies and Experimental<br/>research is( ) A: Intervention or treatment B: Prospective C: Random allocation D: Paralleled control group E: Blinding

The difference in epidemiological experimental studies compared with prospective cohort studies is A: Research direction from outcome to causes B: Established a control group C: Interventions were implemented for the experimental group D: Can be used for cause inference E: Can be used to verify the cause of the hypothesis

The control group A: generally has higher income than the control group B: has no difference with control group C: is group of individules who are not subject to the intervention being studied D: is group of individules who are subject to the intervention being studied