Answer:
See below.
Step-by-step explanation:
1.
2a + 3 * (1 + 2) = 2a + 9: Yes. Expression is equivalent.
2.
33v = (3 * v) * 11: Yes. Expression is equivalent.
3.
3b - 19 + 2b = 3b + 19 - 2b: No. Both expressions are different answers.
4.
4(3c - 4) = 2(6c - 8): No. expressions are not equivalent.
Completely random design is used in this experiment.
In the given question,
A business wants to investigate the efficacy of a novel painkiller.
100 participants who suffer from chronic discomfort are enlisted.
Each participant takes the brand-new painkiller for two weeks before switching to a placebo for an additional two weeks.
The order of the tablets is chosen at random for each participant, and the subjects are unaware of which pill contains the actual medication.
Each subject's variance in total pain will be measured by researchers.
We have to check what type of experiment design is this.
As we can see in the question that they recruit 100 volunteers with chronic pain and each subject they use new pain relief medicine for a 2-week period and a placebo for another 2-week period.
They assign each subject randomly.
As we know that in a completely random design, treatments are randomly assigned to sampling material. The usual method for doing this is to make a list of the treatments and give each one a random number.
So we can see that completely random design is used in this experiment.
To learn more about Completely random design link is here
brainly.com/question/17128981
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