Final answer:
Secondary variables in trials refer to the control of additional factors that could affect the outcome. Randomization and blinding are methods to isolate explanatory variables and mitigate the effects of lurking variables. Trials, such as pharmacokinetic analysis, require considerations like dose/response relationship and participant diversity.
Step-by-step explanation:
When conducting a trial, it is vital to define the explanatory and response variables. The explanatory variable is what the researcher manipulates, while the response variable is the outcome measured. Treatment refers to what is administered to the experimental group in a study.
Participant selection should consider voluntary participation, fairness in selection, confidentiality, potential risks, and societal benefits. Randomly dividing participants into groups who drive without distraction and those who text and drive is essential to isolate the explanatory variable effectively, assuming ethical standards are maintained, and that participants understand the risks involved.
Lurking variables are extraneous variables that can confound the results if not controlled. Blinding, where participants or researchers are unaware of who receives the treatment or the placebo, can help mitigate these variables' effect and protect against expectancy bias.
For a comprehensive trial like a pharmacokinetic analysis in phase II or phase III clinical trials, considering the dose/exposure response is necessary. A wide and diverse participant base is ideal for establishing efficacy and safety profiles.