The most effective in controlling the confounding variables is matched pairs design.
<h3>What is a matched pair design experiment?</h3>
A matched pairs design is when participants are matched based on shared characteristics that is of importance to the experiment. One member of the pair is put in the control group while the other is put in the experimental group.
Here are the options:
A completely randomized design experiment
A longitudinal observational study
A retrospective observational study
A matched-pair design experiment
To learn more about matched-pair design experiment, please check: brainly.com/question/23413412
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4x²-36x/x-9=4x(x-9)/x-9=4x
4x=0
f(0)=0
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Answer:3x^3
Step-by-step explanation:
Step-by-step explanation:
arc length for QT = 2× 71° = 142°