Answer to Question 1
ANS: B
Controlling the treatment or intervention is the most commonly used manipulation.
If the subjects are randomly assigned to the groups, there should be no bias.
Multicausality refers to several concepts or variables being investigated. A single causality, whether interaction with a former patient affects outcomes of CABG, is the focus.
Although the assignment to groups reflects probability, probability is not the process described. Probability looks at the likelihood that all subjects are likely to be represented in the sample.
Answer to Question 2
ANS: B
Controlling the treatment or intervention is the most commonly used manipulation.
Bias is when the researcher shows preference.
Random selection describes a process of ensuring that the sample is representative of the population under study.
Validity refers to the trueness of the tool; is it measuring what it says it measures.