Two essential features of all statistically designed experiments are:

A. Comparing several treatments; using the double-blind method.
B. Comparing several treatments; using chance to assign subjects to treatments.
C. Having a placebo group; using the double-blind method.
D. Using a block design; using chance to assign subjects to treatments.



Answer :

Final answer:

Statistically designed experiments include comparing treatments and assigning subjects randomly to treatment groups while maintaining blinding to prevent bias.


Explanation:

Two essential features of all statistically designed experiments are the comparison of several treatments and chance to assign subjects to treatments. In a well-designed study, subjects are randomly assigned to different treatment groups to eliminate lurking variables, with one group acting as a control group that receives a placebo treatment. The double-blind method ensures that both researchers and subjects are unaware of who is in the control or experimental group to prevent bias.


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