Question

Does talking on the hands-free cell phone distract drivers? Researchers recruit 30 student subjects. Which of the following statements is not a reason for the randomization of the order of the treatments?

1) To eliminate bias in the assignment of treatments
2) To ensure that each treatment has an equal chance of being assigned first
3) To control for any potential confounding variables
4) To increase the statistical power of the study

Answer 1

Randomization in experimental design eliminates bias, ensures equal chances for treatments to be assigned, and controls confounding variables but does not directly increase the statistical power of the study.

Step-by-step explanation:

Researchers use randomization in experimental design to address potential sources of bias and variance that could affect the validity of the study's conclusions. In the context of studying the distractions caused by hands-free cell phone usage while driving, randomization helps in several ways. Firstly, it works to eliminate bias in the assignment of treatments, ensuring that researchers do not inadvertently influence which participants receive each treatment. Secondly, randomization ensures that each treatment has an equal chance of being assigned first, which is crucial to avoid any order effects that could skew the results.

Thirdly, it helps to control for potential confounding variables that might otherwise influence the outcomes. Lastly, while randomization does support the overall integrity of the study, the fourth option saying that it increases the statistical power of the study is not directly related to the role of randomization. Statistical power can be influenced by sample size, effect size, and significance level but is not directly increased by the act of randomization itself.